Apparatus and method for transmitting/receiving downlink data channel signal transmission information in cellular radio communication system using cooperative multi-point scheme

ABSTRACT

An apparatus and a method for transmitting/receiving downlink data channel signal transmission information in a cellular radio communication system using a Cooperative Multi-Point (CoMP) scheme are provided. In the downlink data channel signal transmission information transmission method, a Base Station (BS) transmits downlink data channel signal transmission information including information related to Resource Elements (REs) scheduled for a downlink data channel signal transmission to a User Equipment (UE), and transmits downlink data channel signal non-transmission information including information related to REs through which a downlink data channel signal is not transmitted among the REs scheduled for the downlink data channel signal transmission to the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of prior application Ser.No. 13/740,008, filed on Jan. 11, 2013, which claimed the benefit under35 U.S.C. §119(e) of a United States Provisional Application filed inthe United States Patent and Trademark Office on Feb. 17, 2012 andassigned Ser. No. 61/600,192, a United States Provisional Applicationfiled in the United States Patent and Trademark Office on Feb. 24, 2012and assigned Ser. No. 61/602,741, a United States ProvisionalApplication filed in the United States Patent and Trademark Office onApr. 13, 2012 and assigned Ser. No. 61/623,768, a United StatesProvisional Application filed in the United States Patent and TrademarkOffice on Apr. 17, 2012 and assigned Ser. No. 61/625,252, and a UnitedStates Provisional Application filed in the United States Patent andTrademark Office on Jun. 21, 2012 and assigned Ser. No. 61/662,534, andthe benefit under 35 U.S.C. §119(a) of a Korean patent application filedon Jan. 11, 2012 in the Korean Intellectual Property Office and assignedSerial No. 10-2012-0003435, a Korean patent application filed in theKorean Intellectual Property Office on Feb. 7, 2012 and assigned SerialNo. 10-2012-0012557, a Korean patent application filed in the KoreanIntellectual Property Office on Mar. 14, 2012 and assigned Serial No.10-2012-0026248, and a Korean patent application filed in the KoreanIntellectual Property Office on Aug. 24, 2012 and assigned Serial No.10-2012-0093328, the entire disclosure of each of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and method fortransmitting/receiving downlink data channel signal transmissioninformation in a cellular radio communication system. More particularly,the present invention relates to an apparatus and method fortransmitting/receiving downlink data channel signal transmissioninformation in a Cooperative Multi-Point (CoMP) cellular radiocommunication system in which a plurality of Base Stations (BSs) providea Mobile Station (MS) with a service using a CoMP scheme.

2. Description of the Related Art

A cellular radio communication system has evolved to provide varioushigh-speed large-capacity services to Mobile Stations (MSs). Examples ofthe cellular radio communication system include a High Speed DownlinkPacket Access (HSDPA) mobile communication system, a High Speed UplinkPacket Access (HSUPA) mobile communication system, a Long-Term Evolution(LTE) mobile communication system, a LTE-Advanced (LTE-A) mobilecommunication system, a High Rate Packet Data (HRPD) mobilecommunication system proposed in a 3rd Generation Project Partnership 2(3GPP2), and an Institute of Electrical and Electronics Engineers (IEEE)802.16m mobile communication system.

The LTE mobile communication system has been developed to effectivelysupport a high-speed radio packet data transmission, and may maximize athroughput of a cellular radio communication system using various RadioAccess (RA) schemes. The LTE-A mobile communication system enhances theLTE mobile communication system, and has an enhanced transmissioncapability compared with the LTE mobile communication system.

A 3rd Generation (3G) radio packet data communication system of therelated art such as the HSDPA mobile communication system, the HSUPAmobile communication system and the HRPD mobile communication systemuses schemes such as an Adaptive Modulation and Coding (AMC) scheme anda channel adaptation scheduling scheme in order to enhance atransmission efficiency. Upon using the AMC scheme and the channeladaptation-scheduling scheme, a signal transmission apparatus may use anoptimal modulation scheme and coding scheme at the most efficient timepoint by receiving partial channel status feedback information from asignal reception apparatus.

In a radio packet data communication system using the AMC scheme, asignal transmission apparatus may adjust an amount of data packets to betransmitted according to channel status. That is, if the channel statusis bad, the signal transmission apparatus may keep a reception errorprobability in a target reception error probability which the signaltransmission apparatus targets by decreasing the amount of data packetsto be transmitted. On the other hand, if the channel status is good, thesignal transmission apparatus may keep the reception error probabilityin the target reception error probability and effectively transmit manydata packets by increasing the amount of data packets to be transmitted.

In a radio packet data communication system using the channeladaptation-scheduling scheme, the signal transmission apparatus selectsan MS having good channel status among a plurality of MSs, and providesthe selected MS with a service. So, a system throughput increasescompared with a case where the signal transmission apparatus allocates achannel to an arbitrary MS, and provides the arbitrary MS with theservice. Such system throughput increase is referred to as a ‘multi-userdiversity gain’.

If the AMC scheme is used with a Multiple Input Multiple Output (MIMO)scheme, the AMC scheme may include a function for determining the numberof spatial layers or a rank. In this case, the radio packet datacommunication system using the AMC scheme considers the number of layersto which a packet data is transmitted using the MIMO scheme as well as acode rate and a modulation scheme in order to determine an optimal datarate.

Generally, if an Orthogonal Frequency Division Multiple Access (OFDMA)scheme is used, a system throughput increase is expected compared with acase in which a Code Division Multiple Access (CDMA) scheme is used.

The reason why the system throughput is increased if the OFDMA scheme isused is that a radio packet data communication system may perform afrequency domain-scheduling scheme. The radio packet data communicationsystem may acquire more throughput gains upon using a characteristic ofwhich a channel status is varied according to a frequency like a case inwhich the radio packet data communication system acquires a throughputgain using the channel adaptation-scheduling scheme according to acharacteristic of which a channel status is varied according to time.So, for a next generation cellular radio communication system, researchis performed for changing the CDMA scheme used in a 2nd Generation (2G)cellular radio communication system and a 3G cellular radiocommunication system to the OFDMA scheme. The 3GPP and the 3GPP2 havestarted a standards project related to an enhanced cellular radiocommunication system using the OFDMA scheme.

FIG. 1 schematically illustrates a structure of a radio frame accordingto an LTE-A mobile communication system according to the related art.

Referring to FIG. 1, 1 radio frame includes 10 sub-frames, and each of10 sub-frames includes 2 slots. So, indexes 0 to 9 are allocated to 10sub-frames included in 1 radio frame, and indexes 0 to 19 are allocatedto 20 slots included in 1 sub-frame.

FIG. 2 schematically illustrates a structure of a cellular radiocommunication system according to the related art.

In a cellular radio communication system in FIG. 2, atransmission/reception antenna is arranged at a center in each cell.

Referring to FIG. 2, in a cellular radio communication system includinga plurality of cells, a particular User Equipment (UE) receives a radiocommunication service using a plurality of schemes as described abovefrom a selected cell during a relatively long time, i.e., a semi-statictime interval. For example, it will be assumed that the cellular radiocommunication system includes 3 cells, i.e., a cell 100, a cell 110 anda cell 120. The cell 100 provides a radio communication service to a UE101 and a UE 102, the cell 110 provides a radio communication service toa UE 111, and the cell 120 provides a radio communication service to aUE 121. Base Stations (BSs) 130, 131 and 132 manage the cell 100, thecell 110 and the cell 120, respectively.

The UE 102 receiving the radio communication service using the cell 100is located at a point relatively distant from the BS 130 compared withthe UE 101. The UE 102 suffers from a relatively large interference fromthe BS 132 managing a service region of the cell 120, so the UE 102receives data at a relatively slow data rate.

If the cells 100, 110 and 120 independently provide a radiocommunication service, a BS managing a service region of each of thecells 100, 110 and 120 transmits a Reference Signal (RS) so that aparticular UE measures a downlink channel status of each of the cells100, 110 and 120. If the cellular radio communication system is a 3GPPLTE-A mobile communication system, the RS is a Cell-Specific ReferenceSignal (CRS) or a Channel Status Information Reference Signal (CSI-RS).

Meanwhile, in a 3GPP LTE-A mobile communication system, a UE measures achannel status between a BS and the UE using a CRS or a CSI-RStransmitted in the BS, and feedbacks channel status informationindicating the measured channel status to the BS. Information indicatingthat a reference signal which the UE uses for estimating a channel isthe CRS or the CSI-RS is carried through transmission mode informationwhich the BS transmits to the UE.

In the 3GPP LTE-A mobile communication system, a UE measures channelstatus between a BS and the UE using a CRS or a DeModulation ReferenceSignal (DM-RS) transmitted in the BS, and detects downlink data byperforming a demodulation operation using the measured channel status.Information indicating that a reference signal which the UE uses for thedemodulation operation is the CRS or the DM-RS is carried throughtransmission mode information which the BS transmits to the UE.

FIG. 3 schematically illustrates locations through which a CSI-RS istransmitted in a resource block in an LTE-A mobile communication systemaccording to the related art. Each block in FIG. 3 indicates a ResourceElement (RE) included in a resource block. Referring to FIG. 3, avertical axis denotes a sub-carrier index, and a horizontal axis denotesOrthogonal Frequency Division Multiplexing (OFDM) symbol time.

Each of REs 200-219, CSI-RSs for distinguishing 2 CSI-RS antenna portsmay be transmitted. That is, a particular BS broadcasts 2 CSI-RSs for adownlink measurement through a RE 200. As described in FIG. 2, in acellular radio communication system including a plurality of cells, eachcell allocates a RE included in a resource block, and a CSI-RS istransmitted through the allocated RE. For example, in FIG. 2, a CSI-RSmay be transmitted through the RE 200 in the cell 100, a CSI-RS may betransmitted through a RE 205 in the cell 110, and a CSI-RS may betransmitted through a RE 210 in the cell 120. As described above, in aLTE-A mobile communication system of the related art, the reason whyeach cell transmits a CSI-RS using a different time resource and adifferent frequency resource is to prevent a mutual interference betweenCSI-RSs.

A sub-frame through which a CSI-RS is transmitted may be determinedusing an I_(CSI-RS) as a parameter transmitted through a Radio ResourceControl (RRC) message. Upon receiving the I_(CSI-RS), a UE determinesT_(CSI-RS) as a sub-frame period of a sub-frame through which a CSI-RSis transmitted and Δ_(CSI-RS) as an offset of the sub-frame throughwhich the CSI-RS is transmitted using Table 1.

TABLE 1 CSI-RS periodicity CSI-RS subframe offset CSI-RS-SubframeConfigT_(CSI-RS) Δ_(CSI-RS) I_(CSI-RS) (subframes) (subframes) 0-4 5I_(CSI-RS)  5-14 18 I_(CSI-RS) − 5  15-14 20 I_(CSI-RS) − 15 35-74 40I_(CSI-RS) − 35  75-154 80 I_(CSI-RS) − 75

The UE receives a CSI-RS through a sub-frame satisfying a criteriaexpressed in Equation (1).(10n _(f) +└n _(s)/2┘−Δ_(CSI-RS))mod T _(CSI-RS)=0  Equation (1)where, n_(f) denotes a Radio Frame Number (RFN), and n_(s) denotes aslot number included in a radio frame.

In FIG. 3, a DM-RS may be transmitted through REs 220 and 221. If one ortwo DM-RS transmission ports are used for a data transmission targetinga specific UE, a DM-RS is transmitted through the RE 220, and if morethan two DM-RS transmission ports are used for the data transmissiontargeting the specific UE, the DM-RS is transmitted through the REs 220and 221.

In FIG. 3, a CRS may be transmitted through a RE 231. The CRS istransmitted through a part of the RE 231 or all of the RE 231 accordingto the number of CRS transmission ports in the specific cell. A CRStransmission timing may be changed for each cell. That is, in FIG. 3,the CRS is transmitted at intervals of 3 sub-carriers starting from asub-carrier with a sub-carrier index #0, however, a start position of aCRS transmission for each cell may be determined by applying a modulooperation to a Cell-ID for each cell. For example, the start position ofthe CRS transmission may be determined as a value of Cell-ID mod 6.

After assuming that downlink data, e.g., a Physical Downlink SharedCHannel (PDSCH) signal is not transmitted through a CSI-RS resource, aDM-RS resource, a CRS resource, and a control channel resource, the UEreceives the PDSCH signal through a related resource among remainingresources.

The downlink data is not transmitted through a resource through which aSYNChronization (SYNC) signal is transmitted or a Physical BroadcastCHannel (PBCH) signal is transmitted as well as the resource throughwhich the reference signal is transmitted. For example, the SYNC signalis transmitted through a part of OFDM symbols in sub-frames withsub-frame indexes #0, #5, and the PBCH signal is transmitted through apart of OFDM symbols in a sub-frame with a sub-frame index #0. Thepositions of the SYNC signal transmission and the PBCH signaltransmission are determined according to an LTE-A mobile communicationsystem standard, so the detailed description will be omitted.

In the LTE-A mobile communication system, each sub-frame may be set as aMultimedia Broadcast Multicast Service single Frequency Network (MBSFN)sub-frame, if a specific sub-frame is set as an MBSFN sub-frame, a CRSis not transmitted through resources except for a control channelresource in the specific sub-frame.

An MBSFN sub-frame configuration may be set for each cell, and each ofthe cells may have a different MBSFN sub-frame configuration. An MBSFNsub-frame may be used for a Physical Multicast CHannel (PMCH)transmission or a PDSCH transmission, if the MBSFN sub-frame is used forthe PMCH transmission, an MBSFN reference signal is transmitted as areference signal, and if the MBSFN sub-frame is used for the PDSCHtransmission, a DM-RS and a CSI-RS are transmitted as reference signals.

In the LTE-A mobile communication system assuming thattransmission/reception antennas are deployed at a center of each cell asshown in FIG. 2, a UE may detect a sub-frame number by detecting a SYNCsignal, may detect MBSFN Sub-frame Configuration Information (SCI) andinformation on resources through which a CRS and a CSI-RS aretransmitted by receiving a PBCH signal and cell associated-information,e.g., a System Information Block (SIB), and may detect positioninformation for a DM-RS resource using PDSCH scheduling informationtransmitted through a control channel. So, each UE may receive downlinkdata by detecting a correct position of a resource through which a PDSCHsignal is transmitted.

As described in FIG. 2, in an LTE-A mobile communication system assumingthat a transmission/reception antenna is arranged at a center in eachcell, a UE may detect an System Frame Number (SFN) by detecting a SYNCsignal and detect sub-frames through which a CSI-RS is transmitted andsub-frames, through which a CSI-RS is not transmitted, which arecollided with sub-frames through which a paging signal and systeminformation are transmitted by receiving a PBCH signal and SIB messages.

In a cellular radio communication system in FIG. 2, there is alimitation for providing a high data rate to a UE located at a cellboundary due to interference from another cell. That is, a data rate fora high speed-data service is strongly influenced by a location of a UE.So, in a cellular radio communication system of the related art, it ispossible that a relatively high data rate is provided to a UE locatedrelatively close to a cell center, however, it is difficult for a highdata rate to be provided to a UE located at a relatively far distancefrom a cell center.

In the LTE-A mobile communication system, a CoMP scheme in which aplurality of cells provide a communication service to a particular UEusing a cooperation scheme has been proposed in order to provide a highdata rate to a UE located at a cell boundary, and enlarge a serviceregion providing the high data rate.

In the LTE-A mobile communication system, there is a need for a methodof receiving a downlink data channel signal, e.g., a PDSCH signal byconsidering a reference signal resource, a SYNC signal resource, and aPBCH resource allocated in each of a plurality of cells in order toeffectively use a CoMP scheme. The reference signal resource denotes aresource through which a reference signal is transmitted, the SYNCsignal resource denotes a resource through which the SYNC signal istransmitted, and the PBCH resource denotes a resource through which thePBCH signal is transmitted.

In the LTE-A mobile communication system using the CoMP scheme, there isa need for distinguishing a sub-frame through which a PDSCH signal istransmitted among sub-frames transmitted from a plurality of cells and asub-frame through which a PDSCH signal is not transmitted among thesub-frames in order that the UE effectively receives the PDSCH signal.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present invention.

SUMMARY OF THE INVENTION

Aspects of the present invention are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentinvention is to provide an apparatus and method fortransmitting/receiving downlink data channel signal transmissioninformation in a cellular radio communication system using a CooperativeMulti-Point (CoMP) scheme.

Another aspect of the present invention is to provide an apparatus andmethod for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which aCell-Specific Reference Signal (CRS) is transmitted.

Another aspect of the present invention is to provide an apparatus andmethod for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which a ChannelStatus Information Reference Signal (CSI-RS) is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a system information transmission.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which aSYNChronization (SYNC) signal is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which a PhysicalBroadcast CHannel (PBCH) signal is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which aDeModulation Reference Signal (DM-RS) is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering at least one of a System InformationRadio Network Temporary Identifier (SI-RNTI), a Paging Radio NetworkTemporary Identifier (P-RNTI), a Cell Radio Network Temporary Identifier(C-RNTI), a Semi-Persistent Scheduling Cell Radio Network TemporaryIdentifier (SPS-C-RNTI), and a Random Access Radio Network TemporaryIdentifier (RA-RNTI).

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a Downlink Control Information (DCI)format.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering CoMP associated-schedulinginformation.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information on each of downlink data channel signalstransmitted by a plurality of signal transmission apparatuses in acellular radio communication system using a CoMP scheme.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a CRSis transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which aCSI-RS is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a system informationtransmission.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a SYNCsignal is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a PBCHsignal is transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a DM-RSis transmitted.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering at least one of an SI-RNTI, aP-RNTI, a C-RNTI, an SPS-C-RNTI, and a RA-RNTI.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a DCI format.

Still another aspect of the present invention is to provide an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga CoMP scheme, thereby a signal reception apparatus receives each ofdownlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering CoMP associated-schedulinginformation.

In accordance with one aspect of the present invention, a method fortransmitting downlink data channel signal transmission information by aBase Station (BS) in a cellular radio communication system using a CoMPscheme is provided. The method includes transmitting downlink datachannel signal transmission information including information related toResource Elements (REs) scheduled for a downlink data channel signaltransmission to a User Equipment (UE), and transmitting downlink datachannel signal non-transmission information including informationrelated to REs through which a downlink data channel signal is nottransmitted among the REs scheduled for the downlink data channel signaltransmission to the UE.

In accordance with another aspect of the present invention, a method forreceiving downlink data channel signal transmission information by a UEin a cellular radio communication system using a CoMP scheme isprovided. The method includes receiving downlink data channel signaltransmission information including information related to REs scheduledfor a downlink data channel signal transmission from a Base Station(BS), and receiving downlink data channel signal non-transmissioninformation including information related to REs through which adownlink data channel signal is not transmitted among the REs scheduledfor the downlink data channel signal transmission from the BS.

In accordance with further another aspect of the present invention, a BSin a cellular radio communication system using a CoMP scheme isprovided. The BS includes a transmitter for transmitting downlink datachannel signal transmission information including information related toREs scheduled for a downlink data channel signal transmission to a UE,and for transmitting downlink data channel signal non-transmissioninformation including information related to REs through which adownlink data channel signal is not transmitted among the REs scheduledfor the downlink data channel signal transmission to the UE.

In accordance with still another aspect of the present invention, a UEin a cellular radio communication system using a CoMP scheme isprovided. The UE includes a receiver for receiving downlink data channelsignal transmission information including information related to REsscheduled for a downlink data channel signal transmission from a BS, andfor receiving downlink data channel signal non-transmission informationincluding information related to REs through which a downlink datachannel signal is not transmitted among the REs scheduled for thedownlink data channel signal transmission from the BS.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 schematically illustrates a structure of a radio frame accordingto a Long-Term Evolution-Advanced (LTE-A) mobile communication systemaccording to the related art;

FIG. 2 schematically illustrates a structure of a cellular radiocommunication system according to the related art;

FIG. 3 schematically illustrates locations through which a ChannelStatus Information-Reference Signal (CSI-RS) is transmitted in aresource block in an LTE-A mobile communication system according to therelated art;

FIG. 4 schematically illustrates a structure of a cellular radiocommunication system using a Cooperative Multi-Point (CoMP) schemeaccording to an exemplary embodiment of the present invention;

FIG. 5 schematically illustrates locations of a CSI-RS resource throughwhich a CSI-RS is transmitted in a resource block in a cellular radiocommunication system using a CoMP scheme according to an exemplaryembodiment of the present invention;

FIG. 6 schematically illustrates a method for allocating a CSI-RSresource in a cellular radio communication system using a CoMP schemeaccording to an exemplary embodiment of the present invention;

FIG. 7 schematically illustrates a sub-frame structure in a case where 2cells use different Multimedia Broadcast Multicast Service singleFrequency Network (MBSFN) sub-frame configurations in a cellular radiocommunication system using a CoMP scheme according to an exemplaryembodiment of the present invention;

FIG. 8 schematically illustrates a sub-frame structure in a case where 2cells use different sub-frame indexes in a cellular radio communicationsystem using a CoMP scheme according to an exemplary embodiment of thepresent invention;

FIG. 9 is a flowchart illustrating a method for receiving a PhysicalDownlink Shared CHannel (PDSCH) signal in a User Equipment (UE) in acellular radio communication system using a CoMP scheme according to anexemplary embodiment #1 of the present invention;

FIG. 10 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #2 of the present invention;

FIG. 11 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #3 of the present invention;

FIG. 12 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #4 of the present invention;

FIG. 13 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #5 of the present invention;

FIG. 14 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #6 of the present invention;

FIG. 15 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #7 of the present invention;

FIG. 16 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #9 of the present invention;

FIG. 17 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #10 of the presentinvention;

FIG. 18 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #11 of the presentinvention;

FIG. 19 schematically illustrates an internal structure of a UE in acellular radio communication system using a CoMP scheme according to anexemplary embodiment of the present invention; and

FIG. 20 schematically illustrates an internal structure of a CentralControl Apparatus (CCA) in a cellular radio communication system using aCoMP scheme according to an exemplary embodiment of the presentinvention.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention is provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

In the present disclosure the terms Base Station (BS) and evolved Node B(eNB) may be interchangeably referred to. Similarly, the terms MobileStation (MS) and User Equipment (UE) may be interchangeably referred to.

An exemplary embodiment of the present invention proposes an apparatusand method for transmitting/receiving downlink data channel signaltransmission information in a cellular radio communication system usinga Cooperative Multi-Point (CoMP) scheme.

Another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a resource through which aCell-specific Reference Signal (CRS) is transmitted.

Further another exemplary embodiment of the present invention proposesan apparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a resource through which aChannel Status Information Reference Signal (CSI-RS) is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a system informationtransmission.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a resource through which aSYNChronization (SYNC) signal is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a resource through which aPhysical Broadcast CHannel (PBCH) signal is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a resource through which aDeModulation Reference Signal (DM-RS) is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering at least one of a SystemInformation Radio Network Temporary Identifier (SI-RNTI), a Paging RadioNetwork Temporary Identifier (P-RNTI), a Cell Radio Network TemporaryIdentifier (C-RNTI), a Semi-Persistent Scheduling Cell Radio NetworkTemporary Identifier (SPS-C-RNTI), and a Random Access Radio NetworkTemporary Identifier (RA-RNTI).

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering a Downlink ControlInformation (DCI) format.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives adownlink data channel signal by considering CoMP associated-schedulinginformation.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information on each of downlink data channel signalstransmitted by a plurality of signal transmission apparatuses in acellular radio communication system using a CoMP scheme.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a CRSis transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which aCSI-RS is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a system informationtransmission.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a SYNCsignal is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a PBCHsignal is transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a resource through which a DM-RSis transmitted.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering at least one of an SI-RNTI, aP-RNTI, a C-RNTI, an SPS-C-RNTI, and a RA-RNTI.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering a DCI format.

Still another exemplary embodiment of the present invention proposes anapparatus and method for transmitting/receiving downlink data channelsignal transmission information in a cellular radio communication systemusing a CoMP scheme, thereby a signal reception apparatus receives eachof downlink data channel signals transmitted by a plurality of signaltransmission apparatuses by considering CoMP associated-schedulinginformation.

Exemplary embodiments of the present invention are described below withreference to a Long Term Evolution Advanced (LTE-A) mobile communicationsystem based on an Orthogonal Frequency Division Multiplexing (OFDM)scheme. However, it will be understood by those of ordinary skill in theart that exemplary embodiments of the present invention may be appliedto any one of a High Speed Downlink Packet Access (HSDPA) mobilecommunication system, a High Speed Uplink Packet Access (HSUPA) mobilecommunication system, a Long-Term Evolution (LTE) mobile communicationsystem, a High Rate Packet Data (HRPD) mobile communication systemproposed in a 3rd Generation Project Partnership 2 (3GPP2), an Instituteof Electrical and Electronics Engineers (IEEE) 802.16m mobilecommunication system, etc.

For convenience, it will be assumed that the LTE-A mobile communicationsystem provides a service to a UE using a CoMP scheme, and the downlinkdata channel signal is a Physical Downlink Shared Channel (PDSCH)signal.

Meanwhile, a cellular radio communication system is implemented bydeploying a plurality of cells within a limited region, with each cellproviding a radio communication service to UEs in a related cell througha BS providing the radio communication service. A particular UE onlyreceives the radio communication service from a semi-statically selectedcell. A scheme in which the radio communication service is providedthrough one BS is referred to as a non-Cooperative Multi-Point(non-CoMP) scheme.

In a cellular radio communication system using the non-CoMP scheme, ahigh speed-data rate provided to each of all UEs in a cell extremelyvaries according to a location of each UE. That is, a relativelyhigh-data rate may be provided to a UE located at a cell center,however, it is difficult to provide a relatively high-data rate to a UElocated at a cell boundary.

In the CoMP scheme, a plurality of cells provides a service to a UElocated at a cell boundary by cooperating with one another. The cellularradio communication system using the CoMP scheme may provide an enhancedradio communication service compared with the cellular radiocommunication system using the non-CoMP scheme. For convenience, acellular radio communication system using a CoMP scheme is referred toas ‘cellular CoMP radio communication system’, and a cellular radiocommunication system using a non-CoMP scheme is referred to as ‘cellularnon-CoMP radio communication system’.

Exemplary embodiments of the present invention propose a PDSCH signaltransmission information transmitting/receiving method in which a UE mayeffectively receive PDSCH signals transmitted from a plurality of cellsusing a typical CoMP scheme such as a Dynamic cell Selection (DS)scheme, a Dynamic cell Selection with Dynamic Blanking (DS/DB) scheme, aJoint Transmission (JT), and a Coordinated Scheduling/CoordinatedBeamforming (CS/CB) scheme.

In the DS scheme, a UE measures channel status for each cell, the UEtransmits feedback information indicating the measured channel status toa BS, the BS receiving the feedback information dynamically selects acell which transmits downlink data targeting the UE, and the BStransmits data through the selected cell.

In the DS/DB scheme, a particular cell does not transmit data in orderto decrease interference from the particular cell to other cell. In theJT scheme, a plurality of cells transmits data to a particular UE at thesame time.

In the CS/CB scheme, cooperated cells schedule data and form a beamthrough mutual cooperation thereby reducing mutual interference.

In exemplary embodiments of the present invention, a UE may effectivelyreceive a PDSCH signal by designing a PDSCH signal reception scheme inorder that a CoMP scheme such as a DS scheme, a DS/DB scheme, a JTscheme, and a CS/CB scheme is effectively used in an LTE-A mobilecommunication system using a CoMP scheme.

FIG. 4 schematically illustrates a structure of a cellular radiocommunication system using a CoMP scheme according to an exemplaryembodiment of the present invention.

Referring to FIG. 4, the cellular radio communication system using theCoMP scheme includes 3 cells, and each cell denotes a data transmissionregion to which a particular transmission point may provide a service.Each transmission point may be a Remote Radio Head (RRH) which commonlyuses a Cell IDentifier (Cell-ID) with a macro BS in a macro region, amacro cell or a pico cell in which each transmission point uses adifferent Cell-ID.

In an exemplary embodiment of the present invention, a Central ControlApparatus (CCA) denotes an apparatus such as a Base Station (BS) or aBase Station Controller (BSC) which may transmit/receive data to/from aUE, and process the transmitted/received data. If each transmissionpoint is a RRH which commonly uses a Cell-ID with a macro BS, the macroBS becomes the CCA. If each transmission point is a macro cell or a picocell which uses a different Cell-ID, an apparatus for integrating cellsand managing the integrated cells becomes the CCA.

In FIG. 4, the cellular radio communication system using the CoMP schemeincludes 3 cells 300, 310 and 320, UEs 301, 311 and 321 which receivedata from the closest cell, and a UE 302 which receive data from each ofthe cells 300, 310 and 320 using a CoMP scheme. Each of the UEs 301, 311and 321 which receive the data from the closest cell estimates channelstatus for a cell at which each of the UEs 301, 311 and 321 is locatedusing a reference signal, i.e., a CSI-RS, and transmits feedbackinformation including the channel estimation result to a CCA 330. InFIG. 4, reference signs 331, 332 and 333 indicate BSs managing the cells300, 310 and 320, respectively, and each of the BSs 331, 332 and 333 maycommunicate with the CCA 330.

In FIG. 4, the UE 302 receiving data transmitted from each of the cells300, 310 and 320 using the CoMP scheme should estimate a channel statusfor each cell using cell specific CSI-RSs transmitted from all of thecells 300, 310 and 320. So, the CCA 330 allocates 3 CSI-RS resourcescorresponding to each cell to the UE 302 for a channel estimationoperation performed by the UE 302.

FIG. 5 schematically illustrates locations of a CSI-RS resource throughwhich a CSI-RS is transmitted in a resource block in a cellular radiocommunication system using a CoMP scheme according to an exemplaryembodiment of the present invention.

Each block in FIG. 5 indicates a Resource Element (RE) included in aresource block.

Referring to FIGS. 4 and 5, a CCA 330 allocates 3 CSI-RS resources 401,402 and 403 and transmits a CSI-RS using the 3 CSI-RS resources 401, 402and 403 in order that a UE 302 which receives a CSI-RS using a CoMPscheme may estimate a channel of each of 3 cells 300, 310 and 320 andestimate a channel through which control information and systeminformation are transmitted. That is, a CSI-RS resource through a CSI-RSused for estimating a channel of the cell 300 is transmitted is a RE401, a CSI-RS resource through a CSI-RS used for estimating a channel ofthe cell 310 is transmitted is a RE 402, and a CSI-RS resource through aCSI-RS used for estimating a channel of the cell 320 is transmitted is aRE 403.

A set including a resource through which a CSI-RS, used for a UEreceiving data from a plurality of cells using a CoMP scheme to estimatechannel status for each cell, is transmitted is referred to as ameasurement set. That is, the measurement set includes a resource,allocated to an arbitrary UE, through which the CSI-RS is transmitted.For convenience, a resource through which a CSI-RS is transmitted isreferred to as ‘CSI-RS resource’. The measurement set includes at leastone CSI-RS resource.

In FIG. 5, a CSI-RS resource for 3 cells is allocated in one resourceblock, and transmission timing information on a CSI-RS transmissionsub-frame may be provided to the UE. That is, I_(CSI-RS) in Table 1should be transmitted to CSI-RS resources 401, 402 and 403 for the 3cells. For example, the UE may acquire a T_(CSI-RS) and a Δ_(CSI-RS) inTable 1 as the transmission timing information upon receiving theI_(CSI-RS). Information on the number of transmission antennas whicheach CSI-RS resource uses should be transmitted to the UE. Further,information on transmission power used for each CSI-RS transmissionshould be transmitted to the UE.

If all CSI-RS resources included in a measurement set allocated to a UEwhich receives a downlink data channel signal from each cell using aCoMP scheme are CSI-RS resources allocated for estimating channel statusfor a RRH using a Cell-ID identical to a Cell-ID of a cell which the UEaccesses, i.e., a serving cell, a Cell-Specific Reference Signal (CRS)resource, a SYNC signal resource, a PBCH resource, a transmission timingof a CRS, a transmission timing of a SYNC signal, a transmission timingof a PBCH signal, and a Multimedia Broadcast Multicast Service singleFrequency Network (MBSFN) sub-frame configuration used in cells in whicha downlink data channel signal is transmitted using a CoMP scheme areidentical to a CRS resource, a SYNC signal resource, a PBCH resource, atransmission timing of a CRS, a transmission timing of a SYNC signal, atransmission timing of a PBCH signal, and an MBSFN sub-frameconfiguration used in the serving cell. So, a UE may receive a PDSCHsignal through resources except for the CRS resource, the SYNC signalresource, and the PBCH resource using a scheme identical to a schemeused in an LTE-A mobile communication system of the related art. Here,the CRS resource denotes a resource through which a CRS is transmitted.

However, if at least one of the CSI-RS resources included in themeasurement set is allocated in a cell using a Cell-ID different from aCell-ID of a serving cell, it is not possible for the UE to detect atransmission timing of a CRS, a SYNC signal, and a PBCH signaltransmitted in the cell using the Cell-ID different from the Cell-ID ofthe serving cell using the scheme identical to the scheme used in theLTE-A mobile communication system of the related art. So, the UE may noteffectively receive the PDSCH signal.

An exemplary embodiment #1 to an exemplary embodiment #11 of the presentinvention propose a method for transmitting/receiving PDSCH signaltransmission information thereby UE may effectively receive a PDSCHsignal by considering a CRS transmission timing, a SYNC transmissiontiming, and a PBCH transmission timing. The description for theexemplary embodiment #1 to the embodiment #11 will be followed.

FIG. 6 schematically illustrates a method for allocating a CSI-RSresource in a cellular radio communication system using a CoMP schemeaccording to an exemplary embodiment of the present invention.

Referring to FIG. 6, a vertical axis denotes a sub-carrier index, and ahorizontal axis denotes OFDM symbol time.

A position of a CRS resource allocated in a cell using a Cell-ID 1starts from a sub-carrier #0, and a position of a CRS resource allocatedin a cell using a Cell-ID 2 starts from a sub-carrier #1. So, a UE mayreceive a PDSCH signal through a cell dynamically selected from the cellusing the Cell-ID 1 and the cell using the Cell-ID 2, or may receive thePDSCH signal through the cell using the Cell-ID 1 and the cell using theCell-ID 2. So, available PDSCH resources may be changed according to thecell through which the UE receives the PDSCH signal.

FIG. 7 schematically illustrates a sub-frame structure in a case where 2cells use different MBSFN sub-frame configurations in a cellular radiocommunication system using a CoMP scheme according to an exemplaryembodiment of the present invention.

In FIG. 7, an MBSFN sub-frame which does not include a CRS resource isshown as “MBSFN”, and a normal sub-frame including the CRS resource isshown as “Normal”. For convenience, it is assumed that an MBSFNsub-frame is mainly used for a PDSCH signal transmission.

Referring to FIG. 7, sub-frames #0, #4, #5, #9 are set as normalsub-frames in a Cell 1 and a Cell 2, so a problem occurs that a UEreceives a PDSCH signal by considering which resource among CRSresources allocated in the Cell 1 and the Cell 2 occurs as described inFIG. 6. On the other hand, sub-frames #2, #3, #7, #8 do not include aCRS resource in the Cell 1 and the Cell 2, so the problem does notoccur, and the UE receives a PDSCH signal by considering a DM-RSresource and a CSI-RS resource.

The sub-frame #1 is set as a normal sub-frame in the Cell 1 and set asan MBSFN sub-frame in the Cell 2. So, the sub-frame #1 includes a CRSresource in the Cell 1 and does not include the CRS resource in the Cell2.

That is, the UE may detect that different PDSCH resources are allocatedin each sub-frame based on an MBSFN sub-frame configuration by detectingthe MBSFN sub-frame configuration for cells which allocate CSI-RSresources included in a measurement set.

FIG. 8 schematically illustrates a sub-frame structure in a case where 2cells use different sub-frame indexes in a cellular radio communicationsystem using a CoMP scheme according to an exemplary embodiment of thepresent invention.

Referring to FIG. 8, a sub-frame including a SYNC signal resource isshown as “Synch.”, a sub-frame including a PBCH signal resource is shownas “PBCH”, and a sub-frame including the SYNC signal resource and thePBCH signal resource is “Synch./PBCH”.

In FIG. 8, a sub-frame through which a SYNC signal is transmitted in aCell 1 is different from a sub-frame through which the SYNC signal istransmitted in a Cell 2, and a sub-frame through which a PBCH signal istransmitted in the Cell 1 is different from a sub-frame through whichthe PBCH signal is transmitted in a Cell 2. That is, based on asub-frame index of the Cell 1, a SYNC signal and a PBCH signal for theCell 1 are transmitted through a sub-frame #0, the SYNC signal for theCell 1 is transmitted through a sub-frame #5, a SYNC signal and a PBCHsignal for the Cell 2 are transmitted through a sub-frame #0, whichcorresponds to sub-frame #4 of Cell 1, and the SYNC signal for the Cell2 is transmitted through a sub-frame #5, which corresponds to sub-frame#9 of Cell 1. So, a UE should receive a PDSCH signal through resourcesexcept for a SYNC signal resource or a PBCH resource of the Cell 1 orthe Cell 2 corresponding to a sub-frame index scheduled for a PDSCHsignal transmission.

The description for the exemplary embodiment #1 to the embodiment #11will be followed.

Exemplary Embodiment #1

FIG. 9 is a flowchart illustrating a method for receiving a PDSCH signalin a UE in a cellular radio communication system using a CoMP schemeaccording to an exemplary embodiment #1 of the present invention.

Prior to a description for FIG. 9, in the exemplary embodiment #1 of thepresent invention, a BS transmits a downlink scheduling informationthrough a Physical Downlink Control Channel (PDCCH), and the downlinkscheduling information includes cell information used for a PDSCH signaltransmission. A UE receives a PDSCH signal based on a PDSCH resourcemapping scheme of a related cell after detecting that the PDSCH signaltransmission occurs in which cell using the cell information.

Referring to FIG. 9, a UE receives Measurement Set Information (MSI) andMBSFN Sub-frame Configuration Information (SCI) from a BS in step 911.The BS transmits the MBSFN SCI to the UE using various schemes, and adescription for the various schemes is provided below.

In the first scheme, the BS transmits the MBSFN SCI used in cells whichallocate each of CSI-RS resources included in a measurement set with theMSI to the UE.

For example, if the CSI-RS resources included in the measurement set area CSI-RS-1 resource, a CSI-RS-2 resource, and a CSI-RS-3 resource, itwill be assumed that MSI is {CSI-RS-1, CSI-RS-2, CSI-RS-3}, and MBSFNSCI for each CSI-RS resource is {MBSFN-1, MBSFN-2, MBSFN-3}. The MBSFN-1includes MBSFN SCI used in a cell which allocates the CSI-RS-1 resource,the MBSFN-2 includes MBSFN SCI used in a cell which allocates theCSI-RS-2 resource, and the MBSFN-3 includes MBSFN SCI used in a cellwhich allocates the CSI-RS-3 resource.

The MBSFN SCI may be a value corresponding to a sub-frame index used ina serving cell. On the other hand, the MBSFN SCI may be a valuecorresponding to a sub-frame index used in a cell which allocates aCSI-RS resource. If the MBSFN SCI is the value corresponding to thesub-frame index used in the cell which allocates the CSI-RS resource,the BS should transmit a sub-frame index difference value between thesub-frame index used in the serving cell and the sub-frame index used inthe cell which allocates the CSI-RS resource. In this case, the UE maydetect a MBSFN sub-frame index of a related cell based on the MBSFN SCIand the sub-frame index difference value. For example, the UE may detectthe MBSFN sub-frame index of the related cell by adding the sub-frameindex difference value to the MBSFN SCI.

In the second scheme, the BS transmits Cell-IDs used in cells whichallocate CSI-RS resources included in the measurement set, the MSI, andMBSFN SCI of cells using Cell-IDs different from a Cell-ID used in aserving cell among the Cell-IDs used in the cells which allocate theCSI-RS resources included in the measurement set to the UE.

For example, it will be assumed that MSI and Cell-ID information for aspecific UE is {CSI-RS-1 (Cell-ID-1), CSI-RS-2 (Cell-ID-1), CSI-RS-3(Cell-ID-2)}, and a Cell-ID-1 is a Cell-ID of a serving cell. In thiscase, the BS transmits the MSI, Cell-IDs used in cells which allocateCSI-RS resources included in the measurement set, and MBSFN SCI, i.e.,MBSFN-2 used in a cell using a Cell-ID different from the Cell-ID usedin the serving cell, i.e., a Cell-ID-2 to the UE. In this case, the UEdetects MBSFN SCI of a cell using the Cell-ID-1 using MBSFN SCI of theserving cell included in system information of each cell.

In the third scheme, the BS transmits the MSI, information indicatingwhether each of CSI-RS resources included in the measurement set isallocated in the serving cell, and MBSFN SCI used in a cell differentfrom the serving cell among cells which allocate the CSI-RS resourcesincluded in the measurement set to the UE.

For example, it will be assumed that MSI for a specific UE is {CSI-RS-1,CSI-RS-2, CSI-RS-3}, and the information indicating whether each of theCSI-RS resources included in the measurement set is allocated in theserving cell is a bitmap, i.e., [1, 0, 0]. Here, a value ‘1’ indicatesthat a related CSI-RS resource is a CSI-RS resource allocated in theserving cell, and a value ‘0’ indicates that a related CSI-RS resourceis a CSI-RS resource allocated in a cell different from the servingcell. The BS transmits {MBSFN-2, MBSFN-3} as MBSFN SCI for a CSI-RS-2resource and a CSI-RS-3 resource allocated in the cell different fromthe serving cell to the UE. In this case, the UE detects MBSFN SCI for aCSI-RS-1 resource using MBSFN SCI of the serving cell included in systeminformation of each cell.

Meanwhile, the UE receives PDSCH scheduling information through a PDCCH,and detects information for a cell which transmits a PDSCH signal usingthe PDSCH scheduling information in step 913. If MSI for a specific UEis {CSI-RS-1, CSI-RS-2}, a bitmap including 2 bits is transmitted to thespecific UE, and a PDSCH signal is transmitted in a cell which allocatesa CSI-RS-1 resource if the bitmap is [1, 0]. If the bitmap is [0, 1],the PDSCH signal is transmitted in a cell which allocates a CSI-RS-2resource, and the PDSCH signal is transmitted in the both cells whichallocate the CSI-RS-1 resource and the CSI-RS-2 resource if the bitmapis [1, 1].

The UE detects MBSFN SCI for cells in which a PDSCH signal istransmitted in a scheduled sub-frame in step 915. The UE detects a CRSresource position of cells in which the scheduled sub-frame is set as anormal sub-frame among the cells in which the PDSCH signal istransmitted in the scheduled sub-frame in step 917. The operation ofdetecting the CRS resource position is described below.

When the PDSCH signal is transmitted in one cell, the UE receives thePDSCH signal without considering a CRS resource of a related cell if theCRS resource is set as a MBSFN sub-frame, and the UE detects that thePDSCH signal is not transmitted in a position of the CRS resource if theCRS resource is set as a normal sub-frame.

If the PDSCH signal is transmitted in a plurality of cells at the sametime, the UE detects that the PDSCH signal is not transmitted throughCRS resources set as normal sub-frames among CRS resources allocated inthe plurality of cells. The BS may transmit information on a position ofa CRS resource allocated in a cell different from a serving cell withMSI to the UE, and the operation of transmitting the CRS resourceposition information is described below.

Firstly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting Cell-IDs used in cells which allocate each CSI-RS resourceto the UE.

Secondly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting a start position of a CRS resource to the UE.

Thirdly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting the number of CRS ports with the MSI. In this case, the UEmay detect the position of the CRS resource by assuming that cellsexcept for the serving cell always use 4 CRS ports.

Meanwhile, the UE determines whether there are cells in which a SYNCsignal or a PBCH signal is transmitted in the scheduled sub-frame amongthe cells in which the PDSCH signal is transmitted in the scheduledsub-frame in step 919.

If there are cells in which the SYNC signal or the PBCH signal istransmitted in the scheduled sub-frame among the cells in which thePDSCH signal is transmitted in the scheduled sub-frame, the UE detectsdownlink data by receiving the PDSCH signal through resources except fora CRS resource, a SYNC signal resource or a PBCH resource, a CSI-RSresource, and a DM-RS resource in step 921.

If there are no cells in which the SYNC signal or the PBCH signal istransmitted in the scheduled sub-frame among the cells in which thePDSCH signal is transmitted in the scheduled sub-frame, the UE detectsdownlink data by receiving the PDSCH signal through resources except fora CRS resource, a CSI-RS resource, and a DM-RS resource in step 923.

In FIG. 9, it is assumed that the UE may detect a transmission timing ofthe SYNC signal and the PBCH signal for the cells except for the servingcell.

However, the UE may not detect the transmission timing of the SYNCsignal and the PBCH signal for the cells except for the serving cell. Inthis case, step 919 may be modified as a step in which the UE determineswhether a SYNC signal transmission or a PBCH signal transmission occursin a related sub-frame of the serving cell. That is, the UE receives thePDSCH signal by considering a transmission timing of the SYNC signal andthe PBCH signal for the serving cell if the UE may not detect atransmission timing of the SYNC signal and the PBCH signal for the cellsexcept for the serving cell.

Exemplary Embodiment #2

FIG. 10 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #2 of the present invention.

Prior to a description for FIG. 10, in the exemplary embodiment #2 ofthe present invention, a BS transmits a downlink scheduling informationthrough a PDCCH, and the downlink scheduling information includes cellinformation used for a PDSCH signal transmission. A UE receives a PDSCHsignal based on a PDSCH resource mapping scheme of a related cell afterdetecting that the PDSCH signal transmission occurs in which cell usingthe cell information.

Referring to FIG. 10, a UE receives MSI and MBSFN SCI of cells whichallocate CSI-RS resources included in a measurement set from a BS instep 1011. The UE receives PDSCH scheduling information through a PDCCHfrom the BS, and detects information on a cell which transmits a PDSCHsignal using the PDSCH scheduling information in step 1013. For example,the information on the cell which transmits the PDSCH signal may beimplemented with 1 bit, and the UE interprets the information on thecell which transmits the PDSCH signal as Table 2.

TABLE 2 Information on a cell transmitting a PDSCH signal Interpretation0 A PDSCH signal is transmitted in a serving cell. 1 A PDSCH signal istransmitted in cells which allocate CSI-RS resources included in ameasurement set.

Meanwhile, the information on the cell which transmits the PDSCH signalmay be implemented with 2 bits, and the UE interprets the information onthe cell which transmits the PDSCH signal as Table 3.

TABLE 3 Information on a cell transmitting a PDSCH signal Interpretation00 A PDSCH signal is transmitted in a serving cell. 01 A PDSCH signal istransmitted in the first cell configured by a RRC message. 10 A PDSCHsignal is transmitted in the second cell configured by a RRC message. 11A PDSCH signal is transmitted in cells which allocate CSI-RS resourcesincluded in a measurement set.

As described in Table 3, the UE detects downlink data by receiving thePDSCH signal through resources except for a CRS resource, a PBCHresource, a SYNC signal resource, a CSI-RS resource, and a DM-RSresource included in a related sub-frame if the UE detects that thePDSCH signal is transmitted in the serving cell (information on a celltransmitting a PDSCH signal==00), or the UE detects that the PDSCHsignal is transmitted in the first cell set through a Radio ResourceControl (RRC) message (information on a cell transmitting a PDSCHsignal==01), or the UE detects that the PDSCH signal is transmitted inthe second cell configured by the RRC message (information on a celltransmitting a PDSCH signal==10).

On the other hand, the UE detects downlink data by receiving the PDSCHsignal through resources except for a CRS resource, a PBCH resource, aSYNC signal resource, a CSI-RS resource, and a DM-RS resource which maybe included in a related sub-frame as not an MBSFN sub-frame for thecells which allocate the CSI-RS resources included in the measurementset if the UE detects that the PDSCH signal is transmitted in the cellswhich allocate the CSI-RS resources included in the measurement set(information on a cell transmitting a PDSCH signal==11). The RRC messagein Table 3 includes at least one of the following six pieces ofinformation:

-   -   1. a Cell-ID;    -   2. MBSFN SCI;    -   3. the number of CRS ports;    -   4. CRS resource position information;    -   5. a sub-frame index difference value between a sub-frame index        used in a serving cell and a sub-frame index used in a related        cell; and    -   6. the number of OFDM symbols used for a control channel.

The UE detects MBSFN SCI for cells in which a PDSCH signal istransmitted in a scheduled sub-frame in step 1015. The UE detects a CRSresource position of cells in which the scheduled sub-frame is set as anormal sub-frame among the cells in which the PDSCH signal istransmitted in the scheduled sub-frame in step 1017. The UE detectscells in which a SYNC signal or a PBCH signal is transmitted in thescheduled sub-frame among the cells in which the PDSCH signal istransmitted in the scheduled sub-frame in step 1019. The UE detectsdownlink data by receiving the PDSCH signal through resources except fora CRS resource, a SYNC signal resource, a PBCH resource, a CSI-RSresource, and a DM-RS resource in step 1021.

In FIG. 10, it is assumed that the UE may detect a transmission timingof the SYNC signal and the PBCH signal for the cells except for theserving cell.

However, the UE may not detect the transmission timing of the SYNCsignal and the PBCH signal for the cells except for the serving cell. Inthis case, the UE receives the PDSCH signal by considering atransmission timing of the SYNC signal and the PBCH signal for theserving cell.

Exemplary Embodiment #3

FIG. 11 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #3 of the present invention.

Prior to a description for FIG. 11, in the exemplary embodiment #3 ofthe present invention, a UE receives a PDSCH signal through remainingresources except for all CRS resources, a SYNC signal resource and aPBCH resource after detecting MBSFN SCI for cells which allocate CSI-RSresources included in a measurement set.

Referring to FIG. 11, a UE receives MSI and MBSFN SCI of cells whichallocate CSI-RS resources included in a measurement set from a BS instep 1111. The BS transmits MBSFN SCI for each cell as described beforewith reference to the exemplary embodiment #1 of the present invention,so a detailed description thereof will be omitted herein. The UEreceives PDSCH scheduling information through a PDCCH from the BS instep 1113. The UE detects MBSFN SCI of the cells which allocate theCSI-RS resources included in the measurement set in a scheduledsub-frame in step 1115.

The UE detects a position of a CRS resource of each cell of which thescheduled sub-frame is set as a normal sub-frame among the cells whichallocate the CSI-RS resources included in the measurement set in step1117. That is, the UE detects that a PDSCH signal is not transmitted atpositions of all CRS resources of each cell of which the scheduledsub-frame is set as the normal sub-frame among the cells which allocatethe CSI-RS resources included in the measurement set.

The BS may transmit information on a position of a CRS resourceallocated in a cell different from a serving cell with MSI to the UE,and the operation of transmitting the CRS resource position informationis described below.

Firstly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting Cell-IDs used in cells which allocate each CSI-RS resourceto the UE.

Secondly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting a start position of a CRS resource to the UE.

Thirdly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting the number of CRS ports with the MSI. In this case, the UEmay detect the position of the CRS resource by assuming that cellsexcept for the serving cell always use 4 CRS ports.

Meanwhile, the UE determines whether there are cells in which a SYNCsignal or a PBCH signal is transmitted in the scheduled sub-frame amongthe cells which allocate the CSI-RS resources included in themeasurement set in step 1119.

If there are cells in which the SYNC signal or the PBCH signal istransmitted in the scheduled sub-frame among the cells which allocatethe CSI-RS resources included in the measurement set, the UE detectsdownlink data by receiving the PDSCH signal through resources except fora CRS resource, a SYNC signal resource, a PBCH resource, a CSI-RSresource, and a DM-RS resource in step 1121.

If there are no cells in which the SYNC signal or the PBCH signal istransmitted in the scheduled sub-frame among the cells which allocatethe CSI-RS resources included in the measurement set, the UE detectsdownlink data by receiving the PDSCH signal through resources except fora CRS resource, a CSI-RS resource, and a DM-RS resource in step 1123.

In FIG. 11, it is assumed that the UE may detect a transmission timingof the SYNC signal and the PBCH signal for the cells except for theserving cell.

However, the UE may not detect the transmission timing of the SYNCsignal and the PBCH signal for the cells except for the serving cell. Inthis case, step 1119 may be modified as a step in which the UEdetermines whether a SYNC signal transmission or a PBCH signaltransmission occurs in a related sub-frame of the serving cell. That is,the UE receives the PDSCH signal by considering a transmission timing ofthe SYNC signal and the PBCH signal for the serving cell if the UE maynot detect the transmission timing of the SYNC signal and the PBCHsignal for the cells except for the serving cell.

Exemplary Embodiment #4

FIG. 12 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #4 of the present invention.

Prior to a description for FIG. 12, in the exemplary embodiment #4 ofthe present invention, a UE excludes all available CRS resources fromresources through which the UE receives a PDSCH signal after detectingMBSFN SCI for cells which allocate CSI-RS resources included in ameasurement set. The UE excludes a SYNC signal resource and a PBCHresource from the resources through which the UE receives the PDSCHsignal only if all of the cells which allocate CSI-RS resources includedin the measurement set transmit a SYNC signal and a PBCH signal at thesame time. If at least one of the cells which allocate CSI-RS resourcesincluded in the measurement set does not transmit the SYNC signal andthe PBCH signal, the UE receives the PDSCH signal through a related SYNCsignal resource and PBCH resource without excluding a related resource,i.e., the SYNC signal resource and the PBCH resource from the resourcesthrough which the UE receives the PDSCH signal.

Referring to FIG. 12, a UE receives MSI and MBSFN SCI of cells whichallocate CSI-RS resources included in a measurement set from a BS instep 1211. The BS transmits MBSFN SCI for each cell as described beforewith reference to the exemplary embodiment #1 of the present invention,so a detailed description thereof will be omitted herein.

The UE receives PDSCH scheduling information through a PDCCH from the BSin step 1213. The UE detects MBSFN SCI of the cells which allocate theCSI-RS resources included in the measurement set in a scheduledsub-frame in step 1215. The UE detects a position of a CRS resource ofeach cell of which the scheduled sub-frame is set as a normal sub-frameamong the cells which allocate the CSI-RS resources included in themeasurement set in step 1217. That is, the UE detects that a PDSCHsignal is not transmitted at positions of all CRS resources of each cellof which the scheduled sub-frame is set as the normal sub-frame amongthe cells which allocate the CSI-RS resources included in themeasurement set. The BS may transmit information on a position of a CRSresource allocated in a cell different from a serving cell with MSI tothe UE, and the operation of transmitting the CRS resource positioninformation is described below.

Firstly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting Cell-IDs used in cells which allocate each CSI-RS resourceto the UE.

Secondly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting start position information of a CRS resource to the UE.

Thirdly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting the number of CRS ports with the MSI. In this case, the UEmay detect the position of the CRS resource by assuming that cellsexcept for the serving cell always use 4 CRS ports.

Meanwhile, the UE determines whether all cells which allocate the CSI-RSresources included in the measurement set transmit a SYNC signal or aPBCH signal in the scheduled sub-frame at the same time in step 1219.

If all the cells which allocate the CSI-RS resources included in themeasurement set transmit the SYNC signal or the PBCH signal in thescheduled sub-frame at the same time, the UE detects downlink data byreceiving the PDSCH signal through resources except for a CRS resource,a SYNC signal resource, a PBCH resource, a CSI-RS resource, and a DM-RSresource in step 1221.

If all the cells which allocate the CSI-RS resources included in themeasurement set do not transmit the SYNC signal or the PBCH signal inthe scheduled sub-frame at the same time, that is, if at least one ofall the cells which allocate the CSI-RS resources included in themeasurement set does not transmit the SYNC signal or the PBCH signal inthe scheduled sub-frame, the UE detects downlink data by receiving thePDSCH signal through resources except for a CRS resource, a CSI-RSresource, and a DM-RS resource in step 1223.

In FIG. 12, it is assumed that the UE may detect a transmission timingof the SYNC signal and the PBCH signal for the cells except for theserving cell.

However, the UE may not detect the transmission timing of the SYNCsignal and the PBCH signal for the cells except for the serving cell. Inthis case, step 1219 may be modified as a step in which the UEdetermines whether a SYNC signal transmission or a PBCH signaltransmission occurs in a related sub-frame of the serving cell. That is,the UE receives the PDSCH signal by considering a transmission timing ofthe SYNC signal and the PBCH signal for the serving cell if the UE maynot detect the transmission timing of the SYNC signal and the PBCHsignal for the cells except for the serving cell.

Exemplary Embodiment #5

FIG. 13 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #5 of the present invention.

Prior to a description for FIG. 13, in the exemplary embodiment #5 ofthe present invention, a UE receives a PDSCH signal without consideringa CRS resource if a related sub-frame is set as an MBSFN sub-frame in atleast one cell after detecting MBSFN SCI for cells which allocate CSI-RSresources included in a measurement set.

The UE excludes a SYNC signal resource and a PBCH resource from a PDSCHresource only if all of the cells which allocate the CSI-RS resourcesincluded in the measurement set transmit a SYNC signal and a PBCH signalat the same time, and receives a PDSCH signal without considering arelated resource if at least one of the cells which allocate the CSI-RSresources included in the measurement set does not transmit the SYNCsignal and the PBCH signal. So, the UE receives the PDSCH signal througha cell which allocates maximum resources upon receiving the PDSCH signalbased on the exemplary embodiment #5 of the present invention.

Referring to FIG. 13, a UE receives MSI and MBSFN SCI of cells whichallocate CSI-RS resources included in a measurement set from a BS instep 1311. The BS transmits MBSFN SCI for each cell as described beforewith reference to the exemplary embodiment #1 of the present invention,so a detailed description thereof will be omitted herein. The UEreceives PDSCH scheduling information through a PDCCH from the BS instep 1313. The UE detects MBSFN SCI of the cells which allocate theCSI-RS resources included in the measurement set in a scheduledsub-frame in step 1315.

The UE determines whether a related sub-frame is set as a normalsub-frame in all cells which allocate the CSI-RS resources included inthe measurement set in step 1317. If the related sub-frame is not set asthe normal sub-frame in all the cells which allocate the CSI-RSresources included in the measurement set, the UE detects downlink databy receiving a PDSCH signal through resources except for a CSI-RSresource and a DM-RS resource in step 1319.

If the related sub-frame is set as the normal sub-frame in all the cellswhich allocate the CSI-RS resources included in the measurement set, theUE detects positions of CRS resources of all the cells which allocatethe CSI-RS resources included in the measurement set in step 1321. Thatis, the UE detects that the PDSCH signal is not transmitted through theCRS resources of all the cells which allocate the CSI-RS resourcesincluded in the measurement set. The BS may transmit information on aposition of a CRS resource allocated in a cell different from a servingcell with MSI to the UE, and the operation of transmitting the CRSresource position information is described below.

Firstly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting Cell-IDs used in cells which allocate each CSI-RS resourceto the UE.

Secondly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting start position information of a CRS resource to the UE.

Thirdly, the BS may transmit the information on the position of the CRSresource allocated in the cell different from the serving cell bytransmitting the number of CRS ports with the MSI. In this case, the UEmay detect the position of the CRS resource by assuming that cellsexcept for the serving cell always use 4 CRS ports.

Meanwhile, the UE determines whether all cells which allocate the CSI-RSresources included in the measurement set transmit a SYNC signal or aPBCH signal in the scheduled sub-frame at the same time in step 1323.

If all the cells which allocate the CSI-RS resources included in themeasurement set transmit the SYNC signal or the PBCH signal in thescheduled sub-frame at the same time, the UE detects downlink data byreceiving the PDSCH signal through resources except for a CRS resource,a SYNC signal resource, a PBCH resource, a CSI-RS resource, and a DM-RSresource in step 1325.

If all the cells which allocate the CSI-RS resources included in themeasurement set do not transmit the SYNC signal or the PBCH signal inthe scheduled sub-frame at the same time, that is, if at least one ofall the cells which allocate the CSI-RS resources included in themeasurement set does not transmit the SYNC signal or the PBCH signal inthe scheduled sub-frame, the UE detects downlink data by receiving thePDSCH signal through resources except for a CRS resource, a CSI-RSresource, and a DM-RS resource in step 1327.

In FIG. 13, it is assumed that the UE may detect a transmission timingof the SYNC signal and the PBCH signal for the cells except for theserving cell.

However, the UE may not detect the transmission timing of the SYNCsignal and the PBCH signal for the cells except for the serving cell. Inthis case, step 1323 may be modified as a step in which the UEdetermines whether a SYNC signal transmission or a PBCH signaltransmission occurs in a related sub-frame of the serving cell. That is,the UE receives the PDSCH signal by considering a transmission timing ofthe SYNC signal and the PBCH signal for the serving cell if the UE maynot detect the transmission timing of the SYNC signal and the PBCHsignal for the cells except for the serving cell.

Exemplary Embodiment #6

FIG. 14 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #6 of the present invention.

Prior to a description for FIG. 14, in the exemplary embodiment #1 tothe exemplary embodiment #5 of the present invention, a UE receives aPDSCH signal by considering a DS scheme, a DS/DB scheme, and a JT schemein which cells from which the UE receives the PDSCH signal aredynamically changed. However, in the exemplary embodiment #6 of thepresent invention, the UE receives the PDSCH signal by considering aCS/CB scheme in which the UE receives the PDSCH signal from a servingcell as well as the DS scheme, the DS/DB scheme, and the JT scheme.

So, in the exemplary embodiment #6 of the present invention, a BStransmits a PDSCH_OVERHEAD parameter as a parameter indicating whether aCRS resource, a SYNC signal resource or a PBCH resource which areallocated in cells except for a serving cell among cells which allocateCSI-RS resources included in a measurement set are included in aresource through which a UE receives the PDSCH signal to a UE using aRRC message. The RRC message including the PDSCH_OVERHEAD parameter maybe implemented as a new RRC message or an RRC message of the relatedart. A detailed description of the RRC message including thePDSCH_OVERHEAD parameter will be omitted herein for brevity. The UEdetermines a resource through which the UE receives the PDSCH signalbased on a value of the PDSCH_OVERHEAD parameter.

Here, the PDSCH_OVERHEAD parameter may be implemented with 1 bit. Forexample, a value of the PDSCH_OVERHEAD parameter ‘1(ON)’ indicates thata CRS resource, a SYNC signal resource, or a PBCH resource allocated incells different from a serving cell are included in resources throughwhich the UE receives a PDSCH signal. On the other hand, a value of thePDSCH_OVERHEAD parameter ‘0(OFF)’ indicates that a CRS resource, a SYNCsignal resource, or a PBCH resource allocated in a serving cell areincluded in the resources through which the UE receives the PDSCHsignal. That is, the value of the PDSCH_OVERHEAD parameter ‘1’ indicatesthat the UE receives the PDSCH signal using one of the PDSCH signalreception methods described in the exemplary embodiment #1 to theexemplary embodiment #5 of the present invention. On the other hand, thevalue of the PDSCH_OVERHEAD parameter ‘0’ indicates that the UE receivesthe PDSCH signal by considering the serving cell unlike the exemplaryembodiment #1 to the exemplary embodiment #5 of the present invention.

Referring to FIG. 14, a UE receives MSI from a BS in step 1411. The UEreceives a PDSCH_OVERHEAD parameter from the BS in step 1413. The UEdetermines whether a value of the PDSCH_OVERHEAD parameter is set as 1(a PDSCH_OVERHEAD parameter value==1) in step 1415. If the value of thePDSCH_OVERHEAD parameter is set as 1, the UE detects downlink data byreceiving a PDSCH signal using MBSFN SCI, a position of a CRS resource,a transmission timing of a SYNC signal, and a transmission timing of aPBCH signal for the cells which allocate the CSI-RS resources includedin the measurement set as described before with reference to one of theexemplary embodiment #1 to the exemplary embodiment #5 of the presentinvention in step 1417.

If the value of the PDSCH_OVERHEAD parameter is not set as 1, that is,if the value of the PDSCH_OVERHEAD parameter is set as 0, the UE detectsMBSFN SCI, a position of a CRS resource, a transmission timing of a SYNCsignal, and a transmission timing of a PBCH signal for a serving cell,and detects downlink data by receiving a PDSCH signal through resourcesexcept for a related CRS resource, SYNC signal resource, PBCH resource,CSI-RS resource, and DM-RS resource in step 1419.

Exemplary Embodiment #7

FIG. 15 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #7 of the present invention.

Prior to a description for FIG. 15, in the embodiment #1 to theexemplary embodiment #6 of the present invention, a system informationreception or a paging information reception for a UE using an LTE schemeof the related art is not considered. However, in the exemplaryembodiment #7 of the present invention, a UE receives a PDSCH signal byconsidering the system information reception or the paging informationreception for the UE using the LTE scheme of the related art.

In the exemplary embodiment #7 of the present invention, a BS uses aPDSCH signal transmission method for a serving cell defined in the LTEscheme of the related art if the BS transmits system information orpaging information.

On the other hand, the BS determines resources through which the BStransmits a PDSCH signal by considering a CRS resource, a SYNC signalresource, and a PBCH resource allocated in cells different from aserving cell as well as the serving cell as described in the exemplaryembodiment #1 to the exemplary embodiment #6 of the present invention.The BS generates a related PDCCH by adding a Cyclic Redundancy Check(CRC) generated using an SI-RNTI used in an LTE mobile communicationsystem to related scheduling information in order to schedule atransmission of a PDSCH signal including system information, and uses aCRC generated using a P-RNTI used in the LTE mobile communication systemin order to schedule a transmission of a PDSCH signal including paginginformation.

Referring to FIG. 15, a UE receives PDSCH scheduling information througha PDCCH from a BS in step 1511. The UE determines whether the BS uses aCRC corresponding to an SI-RNTI or a P-RNTI for the PDCCH transmissionin step 1513. If the BS does not use the CRC corresponding to theSI-RNTI or the P-RNTI for the PDCCH transmission, the UE detectsdownlink data by receiving a PDSCH signal using MBSFN SCI, a position ofa CRS resource, a transmission timing of a SYNC signal, and atransmission timing of a PBCH signal for cells which allocate CSI-RSresources included in a measurement set as described before withreference to one of the exemplary embodiment #1 to the exemplaryembodiment #6 of the present invention in step 1515.

If the BS uses the CRC corresponding to the SI-RNTI or the P-RNTI forthe PDCCH transmission, the UE detects MBSFN SCI, a position of a CRSresource, a transmission timing of a SYNC signal, and a transmissiontiming of a PBCH signal for a serving cell, and detects downlink data byreceiving the PDSCH signal through resources except for a related CRSresource, SYNC signal resource, PBCH resource, CSI-RS resource, andDM-RS resource in step 1517.

Exemplary Embodiment #8

In the exemplary embodiment #8 of the present invention, a UE detects acurrent PDSCH resource mapping scheme by interpreting a specific DCIformat included in dynamic scheduling information transmitted through aPDCCH, and detects downlink data by receiving a PDSCH signal based onthe detected PDSCH resource mapping scheme. The specific DCI format maynotify at least one of the following three pieces of CoMP schemeassociated-scheduling information with a PDSCH resource mapping scheme:

-   -   DM-RS sequence information for a PDSCH signal reception;    -   an OFDM symbol position at which the a PDSCH signal reception        should be started (or the number of OFDM symbols used for a        control channel (e.g., a PDCCH) signal transmission); and    -   a relationship between a cell through which a PDSCH signal is        transmitted and a CSI-RS.

The three pieces of CoMP scheme associated-scheduling information andthe PDSCH resource mapping scheme may be changed corresponding to a cellthrough which a PDSCH signal is transmitted, so the three pieces of CoMPscheme associated-scheduling information and the PDSCH resource mappingscheme may be carried through the same DCI format at the same time.

In an LTE mobile communication system, the DM-RS sequence information isdynamically determined according to an n_(SCID) value, and one of twosequences configured by a RRC message is applied as a DM-RS sequence inorder to receive a related PDSCH signal if the n_(SCID) value is set as‘0’ or ‘1’. For example, the n_(SCID) value is determined through a DCIformat implemented with 3 bits, and thus 8 states are possible asdefined in Table 4. That is, the UE may use 2 DM-RS sequences, onecodeword is transmitted if a specific PDSCH signal is transmitted, twocodewords are transmitted if a related DCI format indicates a state #1and a state #3, a DM-RS sequence corresponding to an n_(SCID) value ‘1’is used if the related DCI format indicates the state #1, and a DM-RSsequence corresponding to an n_(SCID) value ‘0’ is used if the relatedDCI format indicates other states.

TABLE 4 One Codeword: Two Codewords: Codeword 0 enabled, Codeword 0enabled, Codeword 1 disabled Codeword 1 enabled Value Message ValueMessage 0 1 layer, port 7, n_(SCID) = 0 0 2 layer, ports 7-8, n_(SCID) =0 1 1 layer, port 7, n_(SCID) = 1 1 2 layer, ports 7-8, n_(SCID) = 1 2 1layer, port 8, n_(SCID) = 0 2 3 layer, ports 7-9 3 1 layer, port 8,n_(SCID) = 1 3 4 layer, ports 7-10 4 2 layer, ports 7-8 4 5 layer, ports7-11 5 2 layer, ports 7-9 5 6 layer, ports 7-12 6 2 layer, ports 7-10 67 layer, ports 7-13 7 Reserved 7 8 layer, ports 7-14

In Table 5, a DM-RS sequence configuration scheme of a BS and a UEaccording to an n_(SCID) value is expressed.

TABLE 5 n_(SCID) DM-RS sequence configuration 0 the first DM-RS sequenceconfigured by a RRC message 1 the second DM-RS sequence configured by aRRC message

Further, the UE may detect CRS resource positions for each cell throughthe following parameters in order to detect available PDSCH resourcesupon considering a DS scheme and a JT scheme in which cells throughwhich the UE receives a PDSCH signal are dynamically changed. Theparameters include:

-   -   1. vshift (=PCID mod 6) or Physical Cell-ID (PCID);    -   2. MBSFN SCI; and    -   3. the number of CRS antenna ports.

So, the BS transmits DM-RS sequence configuration information for aPDSCH signal reception and information on a position of a PDSCH resourceallocable according to a position of a CRS resource for each cell at thesame time as described in Table 6, thereby the UE may dynamically detectDM-RS sequence configuration information and a position of a PDSCHresource according to the n_(SCID) value. That is, if the n_(SCID) valueis set as ‘0’, the UE sets the first DM-RS sequence configured by a RRCmessage, and detects that a PDSCH signal is transmitted throughresources except for a related CRS resource by detecting positioninformation on the first CRS resource configured by the RRC message.

If the n_(SCID) value is set as ‘1’, the UE detects the second DM-RSsequence configuration information and CRS resource positionconfiguration information configured by the RRC message.

TABLE 6 DM-RS CRS resource sequence position n_(SCID) configurationconfiguration 0 1^(st) DM-RS sequence 1^(st) set of [ν_(shift) (orPCID), configured by RRC MBSFN configuration, and # of CRS antennaports] configured by RRC 1 2^(nd) DM-RS sequence 2^(nd) set of[ν_(shift) (or PCID), configured by RRC MBSFN configuration, and # ofCRS antenna ports] configured by RRC

In order to enable the UE to receive a PDSCH signal from more than 2cells in the cellular radio communication system using the CoMP scheme,the BS should notify the UE of additional CRS resource positionconfiguration information as well as the two types of CRS resourceposition configuration information, so the BS may consider an additionalbit as well as the n_(SCID) value as expressed in Table 7. That is, theDM-RS sequence configuration is notified using the n_(SCID) value, theUE may detect one of 4 types of CRS resource position configurationinformation using the additional 1 bit. Upon using DM-RS sequenceconfiguration information and CRS resource position configurationinformation expressed in Table 7, the BS may notify the UE of a changeof a PDSCH resource even though the BS transmits a PDSCH signal usingmore than 3 layers compared with Table 6.

TABLE 7 DM-RS CRS resource additional sequence position n_(SCID) bitconfiguration configuration 0 0 1^(st) DM-RS 1^(st) set of [ν_(shift)sequence (or PCID), configured MBSFN by RRC configuration, and # of CRS0 1 1^(st) DM-RS 2^(nd) set of [ν_(shift) sequence (or PCID), configuredMBSFN by RRC configuration, and # of CRS antenna ports] configured byRRC 1 0 2^(nd) DM-RS 3^(rd) set of [ν_(shift) sequence (or PCID),configured MBSFN by RRC configuration, and # of CRS antenna ports]configured by RRC 1 1 2^(nd) DM-RS 4^(th) set of [ν_(shift) sequence (orPCID), configured MBSFN by RRC configuration, and # of CRS antennaports] configured by RRC

Meanwhile, available PDSCH resources are influenced by the number ofOFDM symbols used for a PDCCH signal transmission as well as a CRSresource position. In an LTE mobile communication system, the first tothe third OFDM symbols in one sub-frame may be used for the PDCCH signaltransmission and the number of the used OFDM symbols may be transmittedto a UE through a Physical Control Format Indication Channel (PCFICH).The number of the used OFDM symbols may be different for each cell, sothe UE may detect a PCFICH for a cell which the UE accesses, i.e., aserving cell. However, it is difficult for the UE to detect PCFICHs forneighbor cells.

So, a UE using a DS scheme or a JT scheme should adjust a start positionof OFDM symbols used for the PDSCH signal transmission corresponding toa cell through which the UE receives the PDSCH signal. In this case, aRRC message used for transmitting the start position of the OFDM symbolsincludes one of the following 4 pieces of information, and the UE mayset the start position of the OFDM symbols using the one of thefollowing 4 pieces of information. The 4 pieces of information include:

-   -   1. information 1: a position of an OFDM symbol, used in a cell        which a UE accesses, in which a PDSCH signal transmission        starts;    -   2. information 2: the second OFDM symbol;    -   3. information 3: the third OFDM symbol; and    -   4. information 4: the fourth OFDM symbol.

If the RRC message includes the information 1, the UE may receive aPDSCH signal corresponding to PDSCH signal transmission start positioninformation set by detecting a PCFICH or using another RRC message for aCarrier Aggregation (CA) scheme.

If the RRC message includes one of the information 2 to the information4, the UE may ignore the PDSCH signal transmission start positioninformation set by detecting the PCFICH or using another RRC message forthe CA scheme and receive the PDSCH signal corresponding to the RRCmessage.

If PDSCH signal transmission start position configuration informationindicating a PDSCH signal transmission start position is added to theDM-RS sequence configuration information and the CRS resource positionconfiguration information as expressed in Table 6, a UE may detect DM-RSsequence configuration information and resources available for a PDSCHsignal transmission according to an n_(SCID) value as expressed in Table8. If the n_(SCID) value is set as 0, the UE may detect DM-RS sequenceconfiguration information and PDSCH resource configuration informationaccording to the first DM-RS sequence configuration information, thefirst CRS resource position configuration information, and the firstPDSCH signal transmission start position configured by a RRC message.

If the n_(SCID) value is set as 1, the UE may detect DM-RS sequenceconfiguration information and PDSCH resource configuration informationaccording to the second DM-RS sequence configuration information, thesecond CRS resource position configuration information, and the secondPDSCH signal transmission start position configured by the RRC message.

TABLE 8 PDSCH transmission start position DM-RS CRS resource (OFDMsymbol sequence position position) n_(SCID) configuration configurationconfiguration 0 1^(st) DM-RS 1^(st) set of [ν_(shift) 1^(st) RRCsequence (or PCID), configuration configured MBSFN for PDSCH by RRCconfiguration, starting OFDM and # of CRS symbol antenna ports]configured by RRC 1 2^(nd) DM-RS 2^(nd) set of [ν_(shift) 2^(nd) RRCsequence (or PCID), configuration configured MBSFN for PDSCH by RRCconfiguration, starting OFDM and # of CRS symbol antenna ports]configured by RRC

If PDSCH signal transmission start position configuration information isadded to the DM-RS sequence configuration information and the CRSresource position configuration information as expressed in Table 7, aUE may detect DM-RS sequence configuration information and PDSCH signaltransmission start information according to an n_(SCID) value and anadditional bit as expressed in Table 9.

TABLE 9 PDSCH transmission start position DM-RS CRS resource (OFDMsymbol additional sequence position position) n_(SCID) bit configurationconfiguration configuration 0 0 1^(st) DM-RS 1^(st) set of [ν_(shift)1^(st) RRC sequence (or PCID), configuration configured MBSFN for PDSCHby RRC configuration, starting OFDM and # of CRS symbol antenna ports]configured by RRC 0 1 1^(st) DM-RS 2^(nd) set of [ν_(shift) 2^(nd) RRCsequence (or PCID), configuration configured MBSFN for PDSCH by RRCconfiguration, starting OFDM and # of CRS symbol antenna ports]configured by RRC 1 0 2^(nd) DM-RS 3^(rd) set of [ν_(shift) 3^(rd) RRCsequence (or PCID), configuration configured MBSFN for PDSCH by RRCconfiguration, starting OFDM and # of CRS symbol antenna ports]configured by RRC 1 1 2^(nd) DM-RS 4^(th) set of [ν_(shift) 4^(th) RRCsequence (or PCID), configuration configured MBSFN for PDSCH by RRCconfiguration, starting OFDM and # of CRS symbol antenna ports]configured by RRC

As described above, information indicating a relationship between a cellthrough which a PDSCH signal is transmitted and a CSI-RS may be carriedwith DM-RS sequence configuration information, CRS resource positionconfiguration information, and PDSCH transmission start positionconfiguration information to a UE. If the UE may detect the relationshipbetween the cell through which the PDSCH signal is transmitted and theCSI-RS, DM-RS channel estimation performance may be improved usingchannel information estimated through a specific CSI-RS upon estimatinga DM-RS channel for a PDSCH signal detection.

Here, the parameter indicating the relationship between the cell throughwhich the PDSCH signal is transmitted and the CSI-RS is transmittedthrough a RRC message, and may include one of the following 4parameters. The 4 parameters include:

-   -   1. parameter 1: the PDSCH signal is transmitted through the        first CSI-RS resource among CSI-RS resources included in the        measurement set;    -   2. parameter 2: the PDSCH signal is transmitted through the        second CSI-RS resource among the CSI-RS resources included in        the measurement set;    -   3. parameter 3: the PDSCH signal is transmitted through the        third CSI-RS resource among the CSI-RS resources included in the        measurement set; and    -   4. parameter 4: the PDSCH signal is not transmitted through the        CSI-RS resources included in the measurement set.

That is, if the parameter indicating the relationship between the cellthrough which the PDSCH signal is transmitted and the CSI-RS is set asone of the parameter 1 to the parameter 3, the UE detects that the PDSCHsignal is transmitted through one of the first CSI-RS resource to thethird CSI-RS resource among the CSI-RS resources included in themeasurement set, and detects the PDSCH signal after estimating a DM-RSchannel using channel information acquired from a related CSI-RS. Theparameter indicating the relationship between the cell through which thePDSCH signal is transmitted and the CSI-RS is transmitted using a RRCmessage. The RRC message including the parameter indicating therelationship between the cell through which the PDSCH signal istransmitted and the CSI-RS may be implemented as a new RRC message or anRRC message of the related art. The detailed description for the RRCmessage including the parameter indicating the relationship between thecell through which the PDSCH signal is transmitted and the CSI-RS willbe omitted.

If the parameter indicating the relationship between the cell throughwhich the PDSCH signal is transmitted and the CSI-RS is set as theparameter 4, the UE does not use the channel information acquired fromthe CSI-RS for estimating the DM-RS channel.

If information indicating a relationship between a cell through which aPDSCH signal is transmitted and a CSI-RS is added to the DM-RS sequenceconfiguration information, the CRS resource position configurationinformation, and the PDSCH transmission start position (OFDM symbolposition) configuration information in Table 8, the UE may detect DM-RSsequence configuration information, a resource available for a PDSCHsignal transmission, and information indicating a relationship betweenDM-RS and a CSI-RS according to an n_(SCID) as expressed in Table 10.

If the n_(SCID) value is set as 0, the UE detects DM-RS sequenceconfiguration information, PDSCH resource configuration information, andDM-RS channel estimation information according to the first DM-RSsequence configuration information, the first CRS resource positionconfiguration information, the first PDCCH resource information, and thefirst relationship information between the DM-RS and the CSI-RSconfigured by a RRC message.

If the n_(SCID) value is set as 1, the UE detects DM-RS sequenceconfiguration information, PDSCH resource configuration information, andDM-RS channel estimation information according to the second DM-RSsequence configuration information, the second CRS resource positionconfiguration information, the second PDCCH resource information, andthe second relationship information between the DM-RS and the CSI-RSconfigured by the RRC message. In Table 10, the relationship informationbetween DM-RS and CSI-RS may be changed to relationship informationbetween a PDSCH signal transmission and a CSI-RS.

TABLE 10 PDSCH transmission relationship DM-RS CRS resource start OFDMinformation sequence position symbol between DM-RS n_(SCID)configuration configuration configuration and CSI-RS 0 1^(st) DM-RS1^(st) set of [ν_(shift) 1^(st) RRC 1^(st) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenantenna ports] CSI-RS configured by and DM-RS RRC (PDSCH) 1 2^(nd) DM-RS2^(nd) set of [ν_(shift) 2^(nd) RRC 2^(nd) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenantenna ports] CSI-RS configured by and DM-RS RRC (PDSCH)

If information for a PDCCH resource is added to the DM-RS sequenceconfiguration information, the CRS resource position configurationinformation, and the PDSCH transmission start position (OFDM symbolposition) configuration information in Table 9, the UE may detect DM-RSsequence configuration information, a resource available for a PDSCHsignal transmission, and information indicating a relationship between aDM-RS and a CSI-RS using an n_(SCID) and an additional bit as expressedin Table 11.

TABLE 11 PDSCH transmission relationship DM-RS CRS resource start OFDMinformation additional sequence position symbol between DM-RS n_(SCID)bit configuration configuration configuration and CSI-RS 0 0 1^(st)DM-RS 1^(st) set of [ν_(shift) 1^(st) RRC 1^(st) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenCSI-RS antenna ports] and DM-RS configured by (PDSCH) RRC 0 1 1^(st)DM-RS 2^(nd) set of [ν_(shift) 2^(nd) RRC 3^(rd) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenCSI-RS antenna ports] and DM-RS configured by (PDSCH) RRC 1 0 2^(nd)DM-RS 3^(rd) set of [ν_(shift) 3^(rd) RRC 4^(th) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenCSI-RS antenna ports] and DM-RS configured by (PDSCH) RRC 1 1 2^(nd)DM-RS 4^(th) set of [ν_(shift) 4^(th) RRC 2^(nd) RRC sequence (or PCID),configuration configuration configured MBSFN for PDSCH for by RRCconfiguration, starting OFDM co-location and # of CRS symbol betweenCSI-RS antenna ports] and DM-RS configured by (PDSCH) RRC

In Table 11, the relationship information between DM-RS and CSI-RS maybe changed to relationship information between a PDSCH signaltransmission and a CSI-RS. In Table 6 to Table 11, each bit state of aDCI format setting DM-RS sequence configuration information, a resourceavailable for a PDSCH signal transmission, and information indicating arelationship between DM-RS and a CSI-RS is determined corresponding toinformation configured by a RRC message. However, it will be understoodby those of ordinary skill in the art that a specific bit state is fixedto specific information without being configured by the RRC message.

For example, in the last state ‘11’ in Table 11, other informationexcept for the DM-RS sequence configuration information is notconfigured by the RRC message and is configured as in Table 12. In thepresent exemplary embodiment, the states except for the state ‘11’ maybe set as Table 12. A part of all pieces of information in Table 12 maybe carried to the UE using a DCI format. In this case, a columnincluding the information carried using the DCI format may be deletedfrom Table 12.

TABLE 12 PDSCH transmission relationship DM-RS CRS resource start OFDMinformation additional sequence position symbol between DM-RS n_(SCID)bit configuration configuration configuration and CSI-RS 1 1 2^(nd)DM-RS a CRS resource a start a PDSCH signal sequence position for aposition is transmitted configured cell which a configuration at a pointat by RRC UE accesses for a cell which a CRS is which a UE transmittedaccesses

Exemplary Embodiment #9/Exemplary Embodiment #10/Exemplary Embodiment#11

In the LTE mobile communication system, the system information and thepaging information are transmitted to all UEs in a cell regardless of UEcapability. That is, the system information and the paging informationare transmitted to Release 8/9/10 UEs as well as Release 11 UEs.

Therefore, a PDSCH RE mapping for the paging information and the systeminformation should use a PDSCH RE mapping equal to a PDSCH RE mappingfor the serving cell. If the UE is scheduled with the system informationor the paging information, a PDCCH for the scheduling uses a CRC of anSI-RNTI or a P-RNTI, respectively.

Therefore, if the UE detects the PDCCH using the P-RNTI or the SI-RNTI,the UE uses the PDSCH RE mapping for the serving cell. On the otherhand, when the UE detects the PDCCH using RNTIs other than the P-RNTIand the SI-RNTI, the UE may use at least one of new PDSCH RE mappingsdescribed below in the methods described with respect to Table 13 orTable 14.

Table 13 and Table 14 are described below.

In LTE Release 10, n_(SCID) is switched between 0 and 1 only for thecase where the UE is scheduled with PDSCH transmission of 1 layer or 2layers. If the UE is configured with PDSCH transmission of more than 2layers, n_(SCID) is fixed to 0. Accordingly, if Table 15 or Table 16 isused, a PDSCH RE mapping cannot be switched between two candidates whenthe UE is scheduled with a PDSCH transmission of more than 2 layers.Therefore, an additional feature may be adopted to facilitate a PDSCH REmapping for supporting a Dynamic Point Selection (DPS) scheme and a JTscheme in a PDSCH transmission of more than 2 layers such as in Table13. Here, the DPS scheme is identical to the DS scheme.

TABLE 13 The Number of layers PDSCH RE mapping 1 or 2 Use Table 15 (orTable 16) More than 2 PDSCH RE mapping for a JT scheme among all CoMPcells

In Table 13, a PDSCH RE mapping for the scheduled number of layers isexpressed.

For Table 13, if a UE is configured with a PDSCH transmission of 1 or 2layers, the UE may assume the PDSCH RE mapping in Table 15 (or Table 16)which is dependent on a value of n_(SCID). On the other hand, if the UEis configured with a PDSCH transmission of more than 2 layers, the UEmay assume the PDSCH RE mapping for the JT scheme among all CoMP cells.As another alternative to Table 13, an entry in the second row and thesecond column can be replaced to a PDSCH RE mapping for the JT schemeamong a set of cells configured by higher layer signaling such as Table14. In this case, additional RRC signaling to indicate a PDSCH REmapping of more than 2 layers should be introduced.

Although, in Table 13 and Table 14, a PDSCH RE mapping is determined bywhether the number of layers of a PDSCH transmission is “1 or 2” or“more than 2”, the present invention may not be restricted to this case.That is, the switching point of a PDSCH RE mapping can be an arbitrarynumber of layers. For example, the PDSCH RE mapping can be determined bywhether the number of layers of a PDSCH transmission is “1” or “morethan 1”. The design assumption on this example is that a PDSCHtransmission of larger than one layer for CoMP UEs can occur only whenthe JT scheme is applied.

TABLE 14 The Number of layers PDSCH RE mapping 1 or 2 Use Table 15 (orTable 16) More than 2 PDSCH RE mapping for the JT scheme among a set ofcells configured by higher layer signaling

In Table 14, a PDSCH RE mapping for the scheduled number of layers isexpressed.

Table 15 and Table 16 are described below.

An indication of a PDSCH RE mapping is tied to a DM-RS scramblingindication. The reason for the joint indication between a DM-RSscrambling and a PDSCH RE mapping is that determination of both a DM-RSscrambling and a PDSCH RE mapping is related to which a TransmissionPoint (TP) is used for the PDSCH transmission.

For one example, the indication of the PDSCH RE mapping can be tied toTable 17 or Table 18 such as Table 15 or Table 16, respectively, whereC_(i) represents a cell and RE_mapping(C₁, C₂, . . . , C_(K)) denotesthe PDSCH RE mapping for the JT scheme among cells C₁, C₂, . . . , C_(K)with K≧1. If K=1, RE_mapping(C₁) denotes the PDSCH RE mapping for thecells C₁.

There are two ways for a UE to decode a PDSCH signal under an assumptionof the PDSCH RE mapping for the JT scheme among multiple cells. Thefirst way is a rate-matching method where UEs decode the PDSCH signalunder an assumption that an eNB maps data bits to REs in order ofskipping CRS positions for multiple cells for the JT scheme as shown inFIG. 16. On the other hand, the second way is a puncturing method wherethe UEs decode the PDSCH signal under an assumption that the eNB mapsthe data bits to the REs in order of the serving cell but punctures theCRS positions for the multiple cells for the JT scheme as shown in FIG.17.

Note that in order for the UE to determine a PDSCH RE mapping for a cellC_(i), the eNB should signal at least one of the following parameters tothe UE:

-   -   a. Physical Cell-ID of C_(i) (or Cell-ID mod 6);    -   b. MBSFN SCI of C_(i);    -   c. Number of CRS port of C_(i);    -   d. Sub-frame offset value of C_(i) from reference        (serving/primary) cell; and    -   e. Number of OFDM symbols to assume for control region.

That is, if Table 15 is used, after two sets of (D1, X1, RE_mapping(C₁,C₂, . . . , C_(K))) and (D2, X2, RE_mapping(C_(K+1), C_(K+2), . . . ,C_(K+L))) are configured for the UE by higher layer signaling, the UEmay use n_(SCID) derived in DCI to determine one of the two sets in onesub-frame scheduled for a PDSCH transmission.

On the other hand, if Table 16 is used, after two pairs of (X1,RE_mapping(C₁, C₂, . . . , C_(K))) and (X2, RE_mapping(C_(K+1), C_(K+2),. . . , C_(K+L))) are configured for the UE by higher layer signaling,the UE may use n_(SCID) derived in DCI to determine one of the two pairsin one sub-frame scheduled for a PDSCH transmission.

As an alternative scheme, the last columns in Table 8 and 9 can includea fixed PDSCH RE mapping method without RRC signaling for the lastcolumns such that “n_(SCID)=0” indicates a PDSCH RE mapping for theserving cell and “n_(SCID)=1” indicates a PDSCH RE mapping for aneighbor cell, or vice versa.

TABLE 15 n_(SCID) Δ_(n) _(SCID) X_(n) _(SCID) PDSCH RE mapping 0 D1 X1RE_mapping(C₁, C₂, . . . , C_(K)) 1 D2 X2 RE_mapping(C_(K+1), C_(K+2), .. . , C_(K+L))

In Table 15, X_(n) _(SCID) , Δ_(n) _(SCID) , and a PDSCH RE mapping forn_(SCID), (K≧1, L≧1) are expressed.

TABLE 16 n_(SCID) X_(n) _(SCID) PDSCH RE mapping 0 X1 RE_mapping(C₁, C₂,. . . , C_(K)) 1 X2 RE_mapping(C_(K+1), C_(K+2), . . . , C_(K+L))

In Table 16, X_(n) _(SCID) and a PDSCH RE mapping for n_(SCID), (K≧1,L≧1) are expressed.

Table 17 and Table 18 are described below.

In one alternative to realize a dynamic adaptation of the DM-RSscrambling sequence, the following initialization value of the DM-RSrandom sequence is used for a UE:c _(init)=(└n _(s,n) _(SCID) /2┘+1)·(2X _(n) _(SCID) +1)·2¹⁶ +n_(SCID)  Equation (2)where n_(SCID) is dynamically determined by DCI between 0 and 1 such asLTE Release 10. Another parameter n_(s,n) _(SCID) in Equation (2) isgiven by n_(s,n) _(SCID) =n_(s)+2Δ_(n) _(SCID) mod 20 where n_(s) is theslot number of the serving (or primary) cell of the UE and Δ_(n) _(SCID)is a sub-frame offset value depending on n_(SCID) in a range of size 10such as [0, 9] or [−4, 5].

One way to determine the parameters n_(s,n) _(SCID) and X_(n) _(SCID) isto use Table 17 where D1, X1, D2, and X2 are signaled by a higher layer.That is, after two pairs of (D1, X1) and (D2, X2) are configured for aUE by higher layer signaling, the UE may use n_(SCID) derived in DCI todetermine one of the two pairs in one sub-frame scheduled for a PDSCHtransmission.

TABLE 17 n_(SCID) Δ_(n) _(SCID) X_(n) _(SCID) 0 D1 X1 1 D2 X2

In Table 17, X_(n) _(SCID) and Δ_(n) _(SCID) for n_(SCID) are expressed.

In another way to determine parameters n_(s,n) _(SCID) and X_(n) _(SCID), X_(n) _(SCID) is determined by Table 18 where X1 and X2 are signaledby the higher layer and n_(s,n) _(SCID) is determined as follows:

-   -   a. If X_(n) _(SCID) =N_(ID) ^(Cell-i), the UE uses a slot number        of Cell-i; and    -   b. If X_(n) _(SCID) ≠N_(ID) ^(Cell-i) for all i, the slot number        is set to a default value (e.g. n_(s,n) _(SCID) =0).        where, N_(ID) ^(Cell-1), N_(ID) ^(Cell-2), . . . , N_(ID)        ^(Cell-M) are Cell-IDs of cells Cell-1, Cell-2, . . . , Cell-M        for which the UE reported Reference Signal Received Power (RSRP)        at least once, or Cell-IDs in a list of physical Cell-IDs which        is signaled by an eNB.

TABLE 18 n_(SCID) X_(n) _(SCID) 0 X1 1 X2

In Table 18, X_(n) _(SCID) for n_(SCID) is expressed.

FIG. 16 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #9 of the present invention.

Referring to FIG. 16, a UE receives a PDCCH signal for a PDSCHscheduling in step 1611. The UE determines whether an SI-RNTI or aP-RNTI has been used for the PDCCH signal in step 1613. If the SI-RNTIand the P-RNTI have not been used for the PDCCH signal, the UE selects anew PDSCH RE mapping in which Table 13 or Table 14 is used in step 1615.

If the SI-RNTI or the P-RNTI has been used for the PDCCH signal, the UEselects a legacy PDSCH RE mapping for a serving cell in step 1617.

The UE receives a PDSCH signal based on the selected PDSCH RE mapping instep 1619.

In a CoMP transmission mode (corresponding to a transmission mode 9 inLTE Release 10), UEs can be scheduled by one of the followingcombinations of DCI format and RNTI in PDCCH (or evolved PDCCH(ePDCCH)):

-   -   a. DCI format 2C and C-RNTI;    -   b. DCI format 2C and SPS C-RNTI;    -   c. DCI format 1A and C-RNTI;    -   d. DCI format 1A and SPS C-RNTI;    -   e. DCI format 1A and P-RNTI;    -   f. DCI format 1A and SI-RNTI;    -   g. DCI format 1A and RA-RNTI;    -   h. DCI format 1C and P-RNTI;    -   i. DCI format 1C and SI-RNTI; and    -   j. DCI format 1C and RA-RNTI.

Here, the C-RNTI is a cell RNTI, the SPS-C-RNTI is a Semi-PersistentScheduling C-RNTI, and the RA-RNTI is a Random Access RNTI.

For the above combinations, the DCI format 2C is used for PDSCHscheduling with up to 8-layer transmission based on a DM-RS and includesindication fields to realize possible dynamic CoMP operations. The DCIformat 1A is used for compact PDSCH scheduling with a small indicationfield.

The DCI format 1C is used for very compact PDSCH scheduling anddedicated to scheduling for paging information and system information,or a random access procedure. Additionally, the C-RNTI is used for datascheduling and the SPS C-RNTI is used for semi-persistent scheduling ofdata. The P-RNTI, SI-RNTI, and RA-RNTI are for scheduling of the paginginformation and the system information, and random access messages,respectively.

For a UE, data is dedicated to the UE such that the data can betransmitted by using a DPS scheme or a JT scheme, while the paginginformation and the system information are broadcast information tomultiple UEs including Release 8/9/10 UEs as well as Release 11 UEs.

The Random access messages are used for various cases including loss ofSYNC for the UE. Based on the discussion on the use of DCI formats andRNTIs, UE assumption on a PDSCH RE mapping for each combination of DCIformat and RNTI in the CoMP transmission mode can be defined as Table19.

TABLE 19 Combination of DCI format and RNTI PDSCH RE mapping DCI format2C and C-RNTI New RE mapping for CoMP DCI format 2C and SPS New REmapping for CoMP C-RNTI DCI format 1A and C-RNTI New RE mapping for CoMPDCI format 1A and SPS New RE mapping for CoMP C-RNTI DCI format 1A andP-RNTI Legacy RE mapping for the serving cell DCI format 1A and SI-RNTILegacy RE mapping for the serving cell DCI format 1A and RA-RNTI LegacyRE mapping for the serving cell DCI format 1C and P-RNTI Legacy REmapping for the serving cell DCI format 1C and SI-RNTI Legacy RE mappingfor the serving cell DCI format 1C and RA-RNTI Legacy RE mapping for theserving cell

In Table 19, New RE mapping for CoMP means at least one of the abovementioned PDSCH RE mapping alternatives for CoMP. Legacy RE mapping forthe serving cell denotes a PDSCH RE mapping method for each case definedin an LTE Release 10 specification.

If UE assumption on a PDSCH RE mapping in Table 19 is used, switchingbetween the new RE mapping and the legacy RE mapping can be based on aRNTI. That is, if the C-RNTI or the SPS RNTI is used for scheduling of aCoMP UE, the new PDSCH RE mapping applies, while the legacy PDSCH REmapping is used if the P-RNTI, the SI-RNTI or the RA-RNTI is used forthe scheduling.

FIG. 17 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #10 of the presentinvention.

Referring to FIG. 17, a UE receives a PDCCH signal for a PDSCHscheduling in step 1711. The UE determines whether a C-RNTI or an SPSC-RNTI has been used for the PDCCH signal in step 1713. If the C-RNTI orthe SPS C-RNTI has been used for the PDCCH signal, the UE selects a newPDSCH RE mapping in which Table 19 is used in step 1715.

If the C-RNTI and the SPS C-RNTI have not been used for the PDCCHsignal, the UE selects a legacy PDSCH RE mapping for a serving cell instep 1717.

The UE receives a PDSCH signal based on the selected PDSCH RE mapping instep 1719.

In FIG. 17, note that the UE can decide a PDSCH RE mapping assumption ofthe UE between a new RE mapping and a legacy RE mapping after the UEdetects both of the DCI format and the RNTI. The decision may be basedon Table 19.

Since DCI format 1A includes a small indication field, the DCI format 1Acould not be appropriate to CoMP scheduling. For this reason, datatransmission of scheduling by the DCI format 1A might not go with a DPSscheme or a JT scheme. Based on this situation for the DCI format 1A, UEassumption on PDSCH RE mapping for each combination of the DCI formatand the RNTI in the CoMP transmission mode can be defined as Table 20.

TABLE 20 Combination of DCI format and RNTI PDSCH RE mapping DCI format2C and C-RNTI New RE mapping for CoMP DCI format 2C and SPS New REmapping for CoMP C-RNTI DCI format 1A and C-RNTI Legacy RE mapping forthe serving cell DCI format 1A and SPS Legacy RE mapping for the servingcell C-RNTI DCI format 1A and P-RNTI Legacy RE mapping for the servingcell DCI format 1A and SI-RNTI Legacy RE mapping for the serving cellDCI format 1A and RA-RNTI Legacy RE mapping for the serving cell DCIformat 1C and P-RNTI Legacy RE mapping for the serving cell DCI format1C and SI-RNTI Legacy RE mapping for the serving cell DCI format 1C andRA-RNTI Legacy RE mapping for the serving cell

In Table 20, a UE assumption on a PDSCH RE mapping is expressed.

If UE assumption on PDSCH RE mapping in Table 20 is used, switchingbetween a new RE mapping and a legacy RE mapping can be based on a DCIformat. That is, if the DCI format 2C is used for scheduling of a CoMPUE, the new PDSCH RE mapping applies, while the legacy PDSCH RE mappingis used if the DCI format 1A or the DCI format 1C is used for thescheduling.

FIG. 18 is a flowchart illustrating a method for receiving a PDSCHsignal in a UE in a cellular radio communication system using a CoMPscheme according to an exemplary embodiment #11 of the presentinvention.

Referring to FIG. 18, a UE receives a PDCCH signal for a PDSCHscheduling in step 1811. The UE determines whether a DCI format 2C hasbeen used for the PDCCH signal in step 1813. If the DCI format 2C hasbeen used for the PDCCH signal, the UE selects a new PDSCH RE mapping inwhich Table 20 is used in step 1815.

If the DCI format 2C has not been used for the PDCCH signal, the UEselects a legacy PDSCH RE mapping for a serving cell in step 1817.

The UE receives a PDSCH signal based on the selected PDSCH RE mapping instep 1819. In FIG. 18, the UE detects whether the DCI format 2C has notbeen used for the PDCCH signal, and selects a PDSCH RE mapping used forthe PDSCH signal reception according to the detecting result. However,it will be understood by those of ordinary skill in the art that the UEselects the legacy PDSCH RE mapping for the serving cell if the DCIformat 2C has been used for the PDCCH signal, and the UE selects the newPDSCH RE mapping if one of various DCI formats such as a DCI format 1A,a DCI format 1C, etc. has been used for the PDCCH signal.

In FIG. 18, note that the UE can decide a PDSCH RE mapping assumption ofthe UE between a new RE mapping and a legacy RE mapping after the UEdetects both of the DCI format and the RNTI. The decision may be basedon Table 20.

For another example, the indication of the PDSCH RE mapping can be tiedto Table 23 or Table 24 such as Table 21 or Table 22, respectively,where C_(i) represents a cell and RE_mapping(C₁, C₂, . . . , C_(K))denotes the PDSCH RE mapping for the JT scheme among cells C₁, C₂, . . ., C_(K) with K≧1. If K=1, RE_mapping(C₁) denotes the PDSCH RE mappingfor the cells C₁. Note that in order for the UE to determine the PDSCHRE mapping for a cell C_(i), an eNB should signal at least one of thefollowing parameters to the UE:

-   -   a. Physical Cell-ID of C_(i) (or Cell-ID mod 6);    -   b. MBSFN sub-frame configuration of C_(i);    -   c. Number of CRS port of C_(i);    -   d. Sub-frame offset value of C_(i) from the reference        (serving/primary) cell; and    -   e. Number of OFDM symbols to assume for control region.

That is, if Table 21 is used, after two sets of (D1, X1, RE_mapping(C₁,C₂, . . . , C_(K))) and (D2, X2, RE_mapping(C_(K+1), C_(K+2), . . . ,C_(K+L))) are configured for the UE by higher layer signaling, the UEmay use n_(SCID2) derived in DCI to determine one of the two sets in onesub-frame scheduled for PDSCH transmission.

On the other hand, if Table 22 is used, after two pairs of (X1,RE_mapping(C₁, C₂, . . . , C_(K))) and (X2, RE_mapping(C_(K+1), C_(K+2),. . . , C_(K+L))) are configured for the UE by higher layer signaling,the UE may use n_(SCID2) derived in DCI to determine one of the twopairs in one sub-frame scheduled for PDSCH transmission.

TABLE 21 n_(SCID2) Δ_(n) _(SCID2) X_(n) _(SCID2) PDSCH RE mapping 0 D1X1 RE_mapping(C₁, C₂, . . . , C_(K)) 1 D2 X2 RE_mapping(C_(K+1),C_(K+2), . . . , C_(K+L))

In Table 21, X_(n) _(SCID2) , Δ_(n) _(SCID2) , and a PDSCH RE mappingfor n_(SCID2), (K≧1, L≧1) are expressed.

TABLE 22 n_(SCID2) X_(n) _(SCID2) PDSCH RE mapping 0 X1 RE_mapping(C₁,C₂, . . . , C_(K)) 1 X2 RE_mapping(C_(K+1), C_(K+2), . . . , C_(K+L))

In Table 22, X_(n) _(SCID) and a PDSCH RE mapping for n_(SCID2), (K≧1,L≧1) are expressed.

Table 23 and Table 24 are described below.

In another alternative to realize a dynamic adaptation of the DM-RSscrambling sequence, the following initialization value of the DM-RSrandom sequence is used for a UE:c _(init)=(└n _(s,n) _(SCID2) /2┘+1)·(2X _(n) _(SCID2) +1)·2¹⁶ +n_(SCID)  Equation (3)where n_(SCID) is dynamically determined by DCI for PDSCH schedulingbetween 0 and 1 like as Release 10 and n_(SCID2) is an additionaldynamic parameter determined by DCI for PDSCH scheduling among integersin a range of [0, N−1].

Further, n_(SCID) and n_(SCID2) can be derived in different two DCIfields or one DCI field jointly coded in a DCI format for PDSCHscheduling. If n_(SCID) and n_(SCID2) have different fields, n_(SCID)would be derived from a legacy 3-bit field indicating antenna port(s),scrambling identity, and number of layers, and n_(SCID2) would bederived from a one bit field or a two bits field with N=2 or N=4,respectively. On the other hand, if n_(SCID) and n_(SCID2) are jointlycoded in one DCI field, n_(SCID) and n_(SCID2) would be derived from 3,4 or 5-bit field indicating antenna port(s), scrambling identity(n_(SCID)), n_(SCID2), and number of layers.

Another parameter n_(s,n) _(SCID2) in Equation (3) is given by n_(s,n)_(SCID2) =n_(s)+2Δ_(n) _(SCID2) mod 20 where n_(s) is the slot number ofthe serving (or primary) cell of the UE and Δ_(n) _(SCID2) is thesub-frame offset value depending on n_(SCID2) in a range of size 10 suchas [0, 9] or [−4, 5]. One way to determine the parameters n_(s,n)_(SCID2) and X_(n) _(SCID2) is to use Table 23 where D1, X1, D2, and X2are signaled by a higher layer.

The assumption in Table 23 is that n_(SCID2) is determined between 0and 1. That is, after two pairs of (D1, X1) and (D2, X2) are configuredfor the UE by higher layer signaling, the UE may use n_(SCID2) derivedin DCI to determine one of the two pairs in one sub-frame scheduled forPDSCH transmission.

TABLE 23 n_(SCID2) Δ_(n) _(SCID2) X_(n) _(SCID2) 0 D1 X1 1 D2 X2

In Table 23, X_(n) _(SCID2) and Δ_(n) _(SCID2) for n_(SCID2) areexpressed.

In another way to determine parameters n_(s,n) _(SCID) and X_(n)_(SCID2) , X_(n) _(SCID2) is determined by Table 24 where X1 and X2 aresignaled by higher layer and n_(s,n) _(SCID2) is determined as follows:

a. If X_(n) _(SCID2) =N_(ID) ^(Cell-i), the UE uses the slot number ofCell-i; and

b. If X_(n) _(SCID2) ≠N_(ID) ^(Cell-i) for all i, the slot number is setto a default value (e.g. n_(s,n) _(SCID2) =0).

where are N_(ID) ^(Cell-1), N_(ID) ^(Cell-2), . . . , N_(ID) ^(Cell-M)Cell-IDs of cells Cell-1, Cell-2, . . . , Cell-M for which the UEreported a RSRP at least once, or Cell-IDs in a list of physicalCell-IDs which is signaled by an eNB.

TABLE 24 n_(SCID2) X_(n) _(SCID2) 0 X1 1 X2

In Table 24, X_(n) _(SCID2) for n_(SCID2) is expressed.

For another example, the indication of the PDSCH RE mapping can be tiedto Table 27 or Table 28 such as Table 25 or Table 26, respectively,where C_(i) represents a cell and RE_mapping(C₁, C₂, . . . , C_(K))denotes the PDSCH RE mapping for the JT scheme among cells C₁, C₂, . . ., C_(K) with K≧1. If K=1, RE_mapping(C₁) denotes the PDSCH RE mappingfor the cells C₁. Note that in order for the UE to determine a PDSCH REmapping for a cell C_(i), an eNB should signal at least one of thefollowing parameters to the UE:

a. Physical Cell-ID of C_(i) (or Cell-ID mod 6);

b. MBSFN sub-frame configuration of C_(i);

c. Number of CRS port of C_(i);

d. Sub-frame offset value of C_(i) from the reference (serving/primary)cell; and

e. Number of OFDM symbols to assume for control region.

That is, if Table 25 is used, after four sets of (D1, X1, RE_mapping(C₁,C₂, . . . , C_(K))), (D2, X2, RE_mapping(C_(K+1), C_(K+2), . . . ,C_(K+L))), (D3, X3, RE_mapping(C_(K+L+1), C_(K+L+2), . . . ,C_(K+L+P))), and (D4, X4, RE_mapping(C_(K+L+P+1), C_(K+L+P+2), . . . ,C_(K+L+P+Q))) are configured for the UE by higher layer signaling, theUE may use (n_(SCID),n_(SCID2)) derived in DCI to determine one of thefour sets in one sub-frame scheduled for PDSCH transmission.

On the other hand, if Table 26 is used, after four pairs of (X1,RE_mapping(C₁, C₂, . . . , C_(K))), (X2, RE_mapping(C_(K+1), C_(K+2), .. . , C_(K+L))), (X3, RE_mapping(C_(K+L+1), C_(K+L+2), . . . ,C_(K+L+P))), and (X4, RE_mapping(C_(K+L+P+1), C_(K+L+P+2), . . . ,C_(K+L+P+Q))) are configured for the UE by higher layer signaling, theUE may use (n_(SCID),n_(SCID2)) derived in DCI to determine one of thefour pairs in one sub-frame scheduled for PDSCH transmission.

TABLE 25 (n_(SCID), n_(SCID2)) Δ_((n) _(SCID) _(, n) _(SCID2) ₎ X_((n)_(SCID) _(, n) _(SCID2) ₎ PDSCH RE mapping (0, 0) D1 X1 RE_mapping(C₁,C₂, . . . , C_(K)) (0, 1) D2 X2 RE_mapping(C_(K+1), C_(K+2), . . . ,C_(K+L)) (1, 0) D3 X3 RE_mapping(C_(K+L+1), C_(K+L+2), . . . ,C_(K+L+P)) (1, 1) D4 X4 RE_mapping(C_(K+L+P+1), C_(K+L+P+2), . . . ,C_(K+L+P+Q))

In Table 25, X_((n) _(SCID) _(,n) _(SCID2) ₎, Δ_((n) _(SCID) _(,n)_(SCID2) ₎, and a PDSCH RE mapping for (n_(SCID),n_(SCID2)), (K≧1, L≧1,P≧1, Q≧1) are expressed.

TABLE 26 (n_(SCID), n_(SCID2)) X_((n) _(SCID) _(, n) _(SCID2) ₎ PDSCH REmapping (0, 0) X1 RE_mapping(C₁, C₂, . . . , C_(K)) (0, 1) X2RE_mapping(C_(K+1), C_(K+2), . . . , C_(K+L)) (1, 0) X3RE_mapping(C_(K+L+1), C_(K+L+2), . . . , C_(K+L+P)) (1, 1) X4RE_mapping(C_(K+L+P+1), C_(K+L+P+2), . . . , C_(K+L+P+Q))

In Table 26, X_((n) _(SCID) _(,n) _(SCID2) ₎ and a PDSCH RE mapping for(n_(SCID),n_(SCID2)), (K≧1, L≧1, P≧1, Q≧1) are expressed.

Table 27 and Table 28 are described below.

In another alternative to realize a dynamic adaptation of the DM-RSscrambling sequence, the following initialization value of the DM-RSrandom sequence is used for a UE:c _(init)=(└n _(s,(n) _(SCID) _(,n) _(SCID2) ₎/2┘+1)·(2X _((n) _(SCID)_(,n) _(SCID2) ₎+1)·2¹⁶ +n _(SCID)  Equation (4)wherein n_(SCID) is dynamically determined by DCI for PDSCH schedulingbetween 0 and 1 such as in Release 10 and n_(SCID2) is an additionaldynamic parameter determined by DCI for the PDSCH scheduling amongintegers in a range of [0, N−1]. Further, n_(SCID) and n_(SCID2) can bederived in different two DCI fields or one DCI field jointly coded in aDCI format for PDSCH scheduling.

If n_(SCID) and n_(SCID2) have different fields, n_(SCID) would bederived from a legacy 3-bit field indicating antenna port(s), scramblingidentity, and number of layers, and n_(SCID2) would be derived from aone bit field or a two bits field with N=2 or N=4, respectively. On theother hand, if n_(SCID) and n_(SCID2) are jointly coded in one DCIfield, n_(SCID) and n_(SCID2) would be derived from 3, 4 or 5-bit fieldindicating antenna port(s), scrambling identity (n_(SCID)), n_(SCID2),and number of layers.

Another parameter, n_(s,(n) _(SCID) _(,n) _(SCID2) ₎ in Equation (4) isgiven by n_(s,(n) _(SCID) _(,n) _(SCID2) ₎=n_(s)+2Δ_((n) _(SCDI) _(,n)_(SCID2) ₎ mod 20 where n_(s) is the slot number of the serving (orprimary) cell of the UE and Δ_((n) _(SCID) _(,n) _(SCID2) ₎ is thesub-frame offset value depending on the pair of (n_(SCID),n_(SCID2)) inthe range of size 10 such as [0, 9] or [−4, 5]. One way to determine theparameters n_(s,(n) _(SCID) _(,n) _(SCID2) ₎ and X_((n) _(SCID) _(,n)_(SCID2) ₎ is to use Table 27 where D1, D2, D3, D4, X1, X2, X3, and X4are signaled by higher layer.

The assumption in Table 27 is that n_(SCID2) is determined between 0and 1. That is, after four pairs of (D1, X1), (D2, X2), (D3, X3) and(D4, X4) are configured for a UE by higher layer signaling, the UE willuse (n_(SCID),n_(SCID2)) derived in DCI to determine one of the fourpairs in one sub-frame scheduled for PDSCH transmission.

TABLE 27 (n_(SCID2), n_(SCID2)) Δ_((n) _(SCID2) _(, n) _(SCID2) ₎ X_((n)_(SCID2) _(, n) _(SCID2) ₎ (0, 0) D1 X1 (0, 1) D2 X2 (1, 0) D3 X3 (1, 1)D4 X4

In Table 27, X_((n) _(SCID) _(,n) _(SCID2) ₎ and Δ_((n) _(SCID) _(,n)_(SCID2) ₎ for (n_(SCID),n_(SCID2)) are expressed.

In another way to determine parameters n_(s,(n) _(SCID) _(,n) _(SCID2) ₎and X_((n) _(SCID) _(,n) _(SCID2) ₎, X_((n) _(SCID) _(,n) _(SCID2) ₎ isdetermined by Table 28 where X1, X2, X3, and X4 are signaled by a higherlayer and n_(s,(n) _(SCID) _(,n) _(SCID2) ₎ is determined as follows:

-   -   a. If X_((n) _(SCID) _(,n) _(SCID2) ₎=N_(ID) ^(Cell-i), the UE        uses the slot number of Cell-i; and    -   b. If X_((n) _(SCID) _(,n) _(SCID2) ₎≠N_(ID) ^(Cell-i) for all        i, the slot number is set to a default value (e.g., n_(s,(n)        _(SCID) _(,n) _(SCID2) ₎=0).        where N_(ID) ^(Cell-1), N_(ID) ^(Cell-2), . . . , N_(ID)        ^(Cell-M) are Cell-IDs of cells Cell-1, Cell-2, . . . , Cell-M        for which the UE reported a RSRP at least once, or Cell-IDs in a        list of physical Cell-IDs which is signaled by an eNB.

TABLE 28 (n_(SCID2), n_(SCID2)) X_((n) _(SCID2) _(, n) _(SCID2) ₎ (0, 0)X1 (0, 1) X2 (1, 0) X3 (1, 1) X4

In Table 28, X_((n) _(SCID) _(,n) _(SCID2) ₎ for (n_(SCID),n_(SCID2)) isexpressed.

FIG. 19 schematically illustrates an internal structure of a UE in acellular radio communication system using a CoMP scheme according to anexemplary embodiment of the present invention.

Referring to FIG. 19, a UE includes a receiver 1911, a controller 1913,a transmitter 1915, and a storage unit 1917.

The controller 1913 controls the overall operation of the UE. Inparticular, the controller 1913 controls the UE to perform an operationof receiving a PDSCH signal according to an exemplary embodiment #1 toan exemplary embodiment #11 of the present invention. The operation ofreceiving the PDSCH signal is performed in the manner described beforewith reference to FIGS. 4 to 18, so a detailed description thereof willbe omitted herein.

The receiver 1911 receives signals from a CCA, a BS, etc. under thecontrol of the controller 1913. The signals received in the receiver1911 are described before with reference to FIGS. 4 to 18, so a detaileddescription thereof will be omitted herein.

The transmitter 1915 transmits signals to the CCA, the BS, etc. underthe control of the controller 1913. The signals transmitted in thetransmitter 1915 are described before with reference to FIGS. 4 to 18,so a detailed description thereof will be omitted herein.

The storage unit 1917 stores the signals received by the receiver 1911and data for the operation of the UE, e.g., information related to theoperation of receiving the PDSCH signal.

While the receiver 1911, the controller 1913, the transmitter 1915, andthe storage unit 1917 are shown in FIG. 19 as separate units, it is tobe understood that this is for merely convenience of description. Inother words, two or more of the receiver 1911, the controller 1913, thetransmitter 1915, and the storage unit 1917 may be incorporated into asingle unit.

FIG. 20 schematically illustrates an internal structure of a CCA in acellular radio communication system using a CoMP scheme according to anexemplary embodiment of the present invention.

Referring to FIG. 20, a CCA includes a receiver 2011, a controller 2013,a transmitter 2015, and a storage unit 2017.

The controller 2013 controls the overall operation of the CCA. Inparticular, the controller 2013 controls the CCA to perform an operationrelated to a PDSCH signal reception operation in a UE according to anexemplary embodiment #1 to an exemplary embodiment #11 of the presentinvention. The operation related to the PDSCH signal reception operationin the UE is performed in the manner described before with reference toFIGS. 4 to 18, so a detailed description thereof will be omitted herein.

The receiver 2011 receives signals from the UE, a BS, etc. under acontrol of the controller 2013. The signals received in the receiver2011 are described before with reference to FIGS. 4 to 18, so a detaileddescription thereof will be omitted herein.

The transmitter 2015 transmits signals to the CCA, the BS, etc. under acontrol of the controller 2013. The signals transmitted in thetransmitter 2015 are described before with reference to FIGS. 4 to 18,so a detailed description thereof will be omitted herein.

The storage unit 2017 stores the signals received by the receiver 2011and data for an operation of the CCA, e.g., information related to thePDSCH signal reception operation in the UE.

While the receiver 2011, the controller 2013, the transmitter 2015, andthe storage unit 2017 are shown in FIG. 20 as separate units, it is tobe understood that this is for merely convenience of description. Inother words, two or more of the receiver 2011, the controller 2013, thetransmitter 2015, and the storage unit 2017 may be incorporated into asingle unit.

As is apparent from the foregoing description, exemplary embodiments ofthe present invention enable a downlink data channel signal transmissioninformation transmission/reception in a cellular radio communicationsystem using a CoMP scheme. Exemplary embodiments of the presentinvention enable a downlink data channel signal transmission informationtransmission/reception in a cellular radio communication system using aCoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which a CRS istransmitted. Exemplary embodiments of the present invention enable adownlink data channel signal transmission informationtransmission/reception in a cellular radio communication system using aCoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a resource through which a CSI-RS istransmitted. Exemplary embodiments of the present invention enable adownlink data channel signal transmission informationtransmission/reception in a cellular radio communication system using aCoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a system information transmission.Exemplary embodiments of the present invention enable a downlink datachannel signal transmission information transmission/reception in acellular radio communication system using a CoMP scheme, thereby asignal reception apparatus receives a downlink data channel signal byconsidering a resource through which a SYNC signal is transmitted.Exemplary embodiments of the present invention enable a downlink datachannel signal transmission information transmission/reception in acellular radio communication system using a CoMP scheme, thereby asignal reception apparatus receives a downlink data channel signal byconsidering a resource through which a PBCH signal is transmitted.Exemplary embodiments of the present invention enable a downlink datachannel signal transmission information transmission/reception in acellular radio communication system using a CoMP scheme, thereby asignal reception apparatus receives a downlink data channel signal byconsidering a resource through which a DM-RS is transmitted. Exemplaryembodiments of the present invention enable a downlink data channelsignal transmission information transmission/reception in a cellularradio communication system using a CoMP scheme, thereby a signalreception apparatus receives a downlink data channel signal byconsidering at least one of a SI-RNTI, a P-RNTI, a C-RNTI, anSPS-C-RNTI, and a RA-RNTI. Exemplary embodiments of the presentinvention enable a downlink data channel signal transmission informationtransmission/reception in a cellular radio communication system using aCoMP scheme, thereby a signal reception apparatus receives a downlinkdata channel signal by considering a DCI format. Exemplary embodimentsof the present invention enable a downlink data channel signaltransmission information transmission/reception in a cellular radiocommunication system using a CoMP scheme, thereby a signal receptionapparatus receives a downlink data channel signal by considering CoMPassociated-scheduling information.

Exemplary embodiments of the present invention enable atransmission/reception for downlink data channel signal transmissioninformation on each of downlink data channel signals transmitted by aplurality of signal transmission apparatuses in a cellular radiocommunication system using a CoMP scheme. Exemplary embodiments of thepresent invention enable a downlink data channel signal transmissioninformation transmission/reception in a cellular radio communicationsystem, thereby a signal reception apparatus receives each of downlinkdata channel signals transmitted by a plurality of signal transmissionapparatuses by considering a resource through which a CRS istransmitted. Exemplary embodiments of the present invention enable adownlink data channel signal transmission informationtransmission/reception in a cellular radio communication system, therebya signal reception apparatus receives each of downlink data channelsignals transmitted by a plurality of signal transmission apparatuses byconsidering a resource through which a CSI-RS is transmitted. Exemplaryembodiments of the present invention enable a downlink data channelsignal transmission information transmission/reception in a cellularradio communication system, thereby a signal reception apparatusreceives each of downlink data channel signals transmitted by aplurality of signal transmission apparatuses by considering a systeminformation transmission. Exemplary embodiments of the present inventionenable a downlink data channel signal transmission informationtransmission/reception in a cellular radio communication system, therebya signal reception apparatus receives each of downlink data channelsignals transmitted by a plurality of signal transmission apparatuses byconsidering a resource through which a SYNC signal is transmitted.Exemplary embodiments of the present invention enable a downlink datachannel signal transmission information transmission/reception in acellular radio communication system, thereby a signal receptionapparatus receives each of downlink data channel signals transmitted bya plurality of signal transmission apparatuses by a plurality of signaltransmission apparatuses by considering a resource through which a PBCHsignal is transmitted. Exemplary embodiments of the present inventionenable a downlink data channel signal transmission informationtransmission/reception in a cellular radio communication system, therebya signal reception apparatus receives each of downlink data channelsignals transmitted by a plurality of signal transmission apparatuses bya plurality of signal transmission apparatuses by considering a resourcethrough which a DM-RS is transmitted. Exemplary embodiments of thepresent invention enable a downlink data channel signal transmissioninformation transmission/reception in a cellular radio communicationsystem, thereby a signal reception apparatus receives each of downlinkdata channel signals transmitted by a plurality of signal transmissionapparatuses by a plurality of signal transmission apparatuses byconsidering at least one of an SI-RNTI, a P-RNTI, a C-RNTI, anSPS-C-RNTI, and a RA-RNTI. Exemplary embodiments of the presentinvention enable a downlink data channel signal transmission informationtransmission/reception in a cellular radio communication system, therebya signal reception apparatus receives each of downlink data channelsignals transmitted by a plurality of signal transmission apparatuses bya plurality of signal transmission apparatuses by considering a DCIformat. Exemplary embodiments of the present invention enable a downlinkdata channel signal transmission information transmission/reception in acellular radio communication system, thereby a signal receptionapparatus receives each of downlink data channel signals transmitted bya plurality of signal transmission apparatuses by a plurality of signaltransmission by considering CoMP associated-scheduling information.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method for wireless communication, the methodcomprising: receiving configuration information including at least twoidentifications for scrambling; receiving control information indicatinga scrambling identity; determining an identification from at least twoidentifications based on the scrambling identity indicated by thecontrol information; and identifying a reference signal based on thescrambling identity and the determined identification.
 2. The method ofclaim 1, further comprising: receiving data using the identifiedreference signal.
 3. The method of claim 1, wherein the configurationinformation is received via a higher layer signaling.
 4. The method ofclaim 1, wherein the control information is received via a physicaldownlink control channel (PDCCH).
 5. The method of claim 1, wherein thedetermined identification of at least two identifications is indicatedby the scrambling identity.
 6. The method of claim 1, wherein thereference signal is identified based on the following initializationvalue,c _(init)=(└n _(s,n) _(SCID) /2┘+1)·(2X _(n) _(SCID) +1)·2¹⁶ +n _(SCID)where n_(SCID) is the scrambling identity, n_(s,n) _(SCID) denotes aslot number, and X_(n) _(SCID) is the determined identification.
 7. Themethod of claim 1, wherein the determining the identification comprises:determining a value of a first parameter corresponding to the scramblingidentity using a mapping table between values of the scrambling identityand values of the first parameter; determining the identificationcorresponding to the value of the first parameter from among the atleast two identifications; and calculating an initialization value beingused for generating the reference signal based on the value of the firstparameter and the determined identification.
 8. An apparatus forwireless communications, the apparatus comprising: a receiver configuredto: receive configuration information including at least twoidentifications for scrambling, and receive control informationindicating a scrambling identity; and a processor configured to:determine an identification from at least two identifications based onthe scrambling identity indicated by the control information, andidentify a reference signal based on the scrambling identity and thedetermined identification.
 9. The apparatus of claim 8, wherein thereceiver is further configured to receive data using the identifiedreference signal.
 10. The apparatus of claim 8, wherein theconfiguration information is received via a higher layer signaling. 11.The apparatus of claim 8, wherein the control information is receivedvia a physical downlink control channel (PDCCH).
 12. The apparatus ofclaim 8, wherein the determined identification of at least twoidentifications is indicated by the scrambling identity.
 13. Theapparatus of claim 8, wherein the reference signal is identified basedon the following initialization value,c _(init)=(└n _(s,n) _(SCID) /2┘+1)·(2X _(n) _(SCID) +1)·2¹⁶ +n _(SCID)where n_(SCID) is the scrambling identity, n_(s,n) _(SCID) denotes aslot number, and X_(n) _(SCID) is the determined identification.
 14. Theapparatus of claim 8, wherein the processor is further configured to:determine a value of a first parameter corresponding to the scramblingidentity using a mapping table between values of the scrambling identityand values of the first parameter; determine the identificationcorresponding to the value of the first parameter from among the atleast two identifications; and calculate an initialization value beingused for generating the reference signal based on the value of the firstparameter and the determined identification.
 15. A method for wirelesscommunications, the method comprising: transmitting, to a userequipment, configuration information including at least twoidentifications for scrambling; transmitting, to the user equipment,control information indicating a scrambling identity; and identifying areference signal based on the scrambling identity and an identificationfrom the at least two identifications, wherein the identification fromthe at least two identifications is determined based on the scramblingidentity indicated by the control information.
 16. The method of claim15, further comprising: transmitting data using the identified referencesignal.
 17. The method of claim 15, wherein the configurationinformation is transmitted via a higher layer signaling.
 18. The methodof claim 15, wherein the control information is transmitted via aphysical downlink control channel (PDCCH).
 19. The method of claim 15,wherein the determined identification of at least two identifications isindicated by the scrambling identity.
 20. The method of claim 15,wherein the reference signal is identified based on the followinginitialization value,c _(init)=(└n _(s,n) _(SCID) /2┘+1)·(2X _(n) _(SCID) +1)·2¹⁶ +n _(SCID)where n_(SCID) is the scrambling identity, n_(s,n) _(SCID) denotes aslot number, and X_(n) _(SCID) is the determined identification.
 21. Themethod of claim 15, wherein the identification of the at least twoidentifications is determined by: determining a value of a firstparameter corresponding to the scrambling identity using a mapping tablebetween values of the scrambling identity and values of the firstparameter; determining the identification corresponding to the value ofthe first parameter from among the at least two identifications; andcalculating an initialization value being used for generating thereference signal based on the value of the first parameter and thedetermined identification.
 22. An apparatus for wireless communications,the apparatus comprising: a transmitter configured to: transmit, to auser equipment, configuration information including at least twoidentifications for scrambling, transmit, to the user equipment, controlinformation indicating a scrambling identity; and a processor configuredto identify a reference signal based on the scrambling identity and anidentification from the at least two identifications, wherein theidentification of the at least two identifications is determined basedon the scrambling identity indicated by the control information.
 23. Theapparatus of claim 22, wherein the transmitter is further configured totransmit data using the identified reference signal.
 24. The apparatusof claim 22, wherein the configuration information is transmitted via ahigher layer signaling.
 25. The apparatus of claim 22, wherein thecontrol information is transmitted via a physical downlink controlchannel (PDCCH).
 26. The apparatus of claim 22, wherein the determinedidentification of at least two identifications is indicated by thescrambling identity.
 27. The apparatus of claim 22, wherein thereference signal is identified based on the following initializationvalue,c _(init)=(└n _(s,n) _(SCID) /2┘+1)·(2X _(n) _(SCID) +1)·2¹⁶ +n _(SCID)where n_(SCID) is determined between 0 and 1 based on the scramblingidentity, n_(s,n) _(SCID) denotes a slot number, and X_(n) _(SCID) isdetermined based on the determined identification.
 28. The apparatus ofclaim 22, wherein the identification of the at least two identificationsis determined by: determining a value of a first parameter correspondingto the scrambling identity using a mapping table between values of thescrambling identity and values of the first parameter; determining theidentification corresponding to the value of the first parameter fromamong the at least two identifications; and calculating aninitialization value being used for generating the reference signalbased on the value of the first parameter and the determinedidentification.